Author: Jared Purkey

Key Points

• A koi pond is a decorative, fish-focused water feature designed for visual enjoyment and minimal interaction, requiring annual maintenance and a biological filtration system.
• A recreation pond is a swimmable, chemical-free ecosystem built for active use, needing more space and advanced natural filtration.
• Koi ponds cost less to install and maintain, while recreation ponds offer higher long-term value and biodiversity in larger yards.

Making a Splash: Finding the Right Pond for Your Backyard

Dreaming of a peaceful koi pond or a backyard oasis where the kids can splash around on hot afternoons?

Wondering which pond option actually makes the most sense for your space and your lifestyle?

In this guide, you’ll get a side-by-side breakdown of koi ponds and recreation ponds, covering their purpose, features, maintenance needs, and costs.

Whether you’re in Discovery Bay, Brentwood, or a nearby community, you’ll come away with a clear understanding of which type of pond fits your home and goals best.

If you’re ready to add a water feature but don’t know where to start, give California Aqua Pros a call or fill out the contact form.

We’ll help you figure out which pond design will bring your outdoor space to life.

What Is a Koi Pond?

A koi pond is a custom-built water feature designed primarily to house and showcase koi fish in a tranquil, decorative setting.

Unlike conventional ponds, these systems are carefully engineered to provide clear water, stable conditions, and a visually relaxing space for homeowners.

Definition and Primary Purpose

• Built for ornamental enjoyment, not for swimming.
• Ideal for observing the graceful movement and vibrant colors of koi.
• Prioritizes a calm surface and healthy conditions for fish.

Common Features

• A layered biological filtration system to keep fish waste and debris under control.
• Clean gravel, decorative rocks, and a balanced use of aquatic plants to support filtration and create a natural feel.
• Gentle waterfalls or spillways for oxygenation and sound.

Maintenance Requirements

• Periodic filter cleanings and seasonal care to prepare for winter or hot summers.
• Monitoring of your koi fish for signs of stress or disease.

Who It’s Best For

• Homeowners who love nature and want a peaceful, low-activity water garden.
• People interested in koi, goldfish, or other ornamental species.
• Those who want a manageable, decorative pond that doesn’t require fences or lifeguard-level safety.

What Is a Recreation Pond?

A recreational pond, also called a natural swimming pond or swim pond, is designed for both beauty and function.

Think of it as a natural swimming pool that’s safe, chemical-free, and filled with life instead of chlorine.

Definition and Primary Purpose

• Built for swimming, lounging, and play—without harsh chemicals.
• Mimics the look and feel of a naturalistic water body while remaining carefully controlled behind the scenes.
• Uses plants and filtration zones to maintain clean, swimmable water.

Key Design Elements

• Larger footprint and unique shape to separate swim zones from filtration areas.
• Often includes planted regeneration zones and aeration systems.
• May feature rocks, gravel beaches, or natural stream designs for added appeal.

Function and Use

• Perfect for warm California summers, offering the feel of a lake without leaving your backyard.
• Allows you to float, dip, and relax while enjoying a balanced ecosystem.
• Also supports wildlife, adding more life to your landscape.

Who It’s Best For

• Families who want an eco-friendly alternative to a traditional pool.
• Homeowners with ample space who are ready to maintain a more complex system.
• Those looking for a swimming solution that blends naturally into their environment.

Core Differences Between Koi Ponds and Recreation Ponds

Choosing between a koi pond and a recreational pond comes down to how you want to use your outdoor space.

Whether you’re focused on creating a peaceful water garden or a family-friendly swimming zone, knowing the differences makes all the difference.

Purpose and Use

• A koi pond is all about visual enjoyment and caring for ornamental fish like koi in a controlled, peaceful setting.
• A recreational pond or natural swimming pool is built for interaction—floating, wading, and active use during the warmer months.

Design and Space Requirements

• Koi ponds can be compact and typically sit closer to patios or high-visibility spots in the landscape.
• Swim ponds require more ground space, a minimum depth for safe entry, and often feature separate zones for plants, filtration, and swimming.

Filtration and Water Management

• A koi pond relies on a carefully tuned biological filtration system and skimmer to remove fish waste and protect sensitive species from poor water quality. We install premium Aquascape BioFalls filters in all of our koi ponds.
• A recreational pond uses skimmers, biological filtration systems, and natural plant zones to maintain clear water without harmful chemicals.

Safety Considerations

• Koi ponds are shallow and do not require fencing in most areas.
• Backyard recreation ponds, especially those used like a swimming pool, must be built with proper grading and safety planning for families.

Lifestyle and Maintenance Considerations

If you’re deciding between a koi pond and a natural swimming pool, understanding what it takes to maintain each type will help you make the right call for your home.

Time Commitment

• A koi pond is low maintenance but needs steady attention: annual cleaning, daily feeding, and seasonal maintenance.
• Swim ponds operate on a larger scale but also require very little maintenance when designed with proper filtration and aeration systems.

Maintenance Routines

• Koi pond tasks include:
  • Emptying skimmer basket
  • Adding beneficial bacteria weekly
  • Monitoring water quality
  • Cleaning the skimmer filter pad (this is different from the BioFalls filter which should only be cleaned once a year)
  • Removing debris and trimming plants
• Recreational pond tasks may include:
  • Checking the filtration system and skimmers
  • Managing the plant zones
  • Keeping an eye on circulation pumps

Seasonal Care

• In winter, koi will go into hibernation. We do cleanouts while the fish are dormant during the winter.
• With swim ponds, you’ll need to occasionally cut back plants, remove algae, and prep equipment for cold or wet weather.

Both options offer beauty and fun—but their upkeep styles are slightly different.

Pick the pond that matches your pace and lifestyle.

Environmental and Health Benefits

Whether you’re building a peaceful koi pond or an interactive swimming pool-style pond, both options can be eco-friendly, safe, and great for your overall landscape.

In the East Bay area, where summers are warm and backyards are often extensions of the home, these water features can add more than just visual value.

Ecosystem Balance

• A well-designed koi pond supports a controlled environment where beneficial bacteria break down fish waste, keeping the water quality in check.
• Swim ponds create a more expansive ecosystem that mimics natural bodies of water, using plants, gravel, and rocks to process excess nutrients and limit algae growth.

Wildlife and Biodiversity

• Both pond types attract birds, dragonflies, and frogs, adding life to your water garden.
• Swim ponds tend to support more biodiversity due to their deeper, multi-zone design and broader ecological footprint.

Chemical-Free Water

• Koi ponds need clean, fish-safe water, managed through a biological filter and regular low-maintenance routine.
• Unlike a traditional pool, natural swim ponds skip the chemicals and rely on balanced biology to stay clear—no chlorine, no harsh additives.

In both cases, you’re not just building a feature—you’re nurturing a healthy system that contributes to your backyard’s overall quality of life.

Cost Comparison: Koi Pond vs. Recreation Pond

As a pond owner, choosing between a koi pond and a recreational pond often comes down to budget.

While both add value to your property, the cost of installation and ongoing care can vary quite a bit depending on the size, complexity, and features involved.

Installation Costs

• A koi pond generally costs less upfront due to its smaller footprint and simpler system. Fewer materials and a smaller filtration setup help keep expenses down. Follow the link to learn the basics of how to build a koi pond.
• Swim ponds are a bigger investment, similar to a swimming pool. Excavation, waterfalls, plumbing zones, and multi-level filtration systems drive the cost higher.

The best way to get an exact quote for your project is to contact a professional water feature contractor for a consultation.

Ongoing Expenses

• Maintaining a koi pond means routine spending on filter replacements, koi food, and annual cleanouts.
• A natural swimming pool has lower cleaning costs than a traditional pool, but it still uses power for pumps and circulation and may need occasional equipment service.

Property Value Impact

• Both styles improve resale value by enhancing your outdoor living space.
• A well-executed swim pond often offers a stronger return on investment because it functions like a pool but blends more seamlessly into a natural backyard.

No matter which you choose, investing in high water quality and thoughtful design ensures your pond remains beautiful and enjoyable for years to come.

How to Choose the Right Pond for Your Backyard

If you’re a pond owner or future one in the East Bay area, choosing between a decorative water garden and a fully swimmable pond comes down to how you plan to enjoy your outdoor space.

Decision-Making Checklist

Ask yourself these questions before committing to either a koi pond or swim pond:

• Do I want a place to relax and watch fish, or do I want to jump in and cool off?
• How much space can I dedicate to the pond, and does it support a deeper footprint?
• Do I want to build a peaceful ecosystem pond’s water feature, or a multi-use zone for family, guests, or kids?

Questions to Ask a Pro

A trusted pond builder can debunk pond myths, help you avoid a costly mistake and get the most from your investment.

Be sure to ask:

• What type of pond fits my soil, sun exposure, and long-term goals?
• Which design best supports a healthy ecosystem and fits into my landscape?
• Will my system require beneficial bacteria, aeration, or a specific type of filter?
• How much will it cost to maintain either pond long-term?

There’s no one-size-fits-all solution.

Your perfect pond depends on your lifestyle, your yard, and how you want to interact with your water garden day-to-day.

Koi or Recreation? California Aqua Pros Can Build the Pond You’ve Been Dreaming Of

Now that you understand the difference between a koi pond and a swim pond, you’re better equipped to choose the right water feature for your space, your lifestyle, and your long-term goals.

Whether you’re looking for a peaceful water garden or a chemical-free swimming pool alternative, the right pond will add beauty, functionality, and lasting value to your backyard.

If you’re ready to turn your vision into reality, California Aqua Pros has been building ponds across the East Bay area for over 30 years.

From compact koi setups to large ecosystem swim zones, our pond construction experts design and install ponds that blend seamlessly into your landscape and lifestyle.

Key Points

• Murky water, falling water levels, and recurring algae blooms are early signs your pond needs repair due to leaks, poor filtration, or nutrient imbalance.
• Strange odors, bubbling, and odd equipment noises signal malfunctioning pumps or buildup of organic waste that disrupts your pond’s ecosystem.
• Koi gasping, dead fish, or rotting plants suggest poor oxygen levels or water quality, often requiring structural fixes or a full pond remodel.

Ripple Effects: Don’t Let Small Pond Problems Spiral

Noticed your pond water getting murkier or your koi acting a little off lately?

Wondering if that low waterline or constant algae bloom is just a fluke—or something more serious?

In this post, we’ll walk you through the key warning signs your backyard pond might need repair, explain what’s causing them, and show you how to stay ahead of the damage.

Catching issues early can save you time, money, and a lot of headaches—while keeping your pond looking clear, balanced, and beautiful.

If something doesn’t seem quite right with your pond in Brentwood, Discovery Bay, or a nearby area, reach out to California Aqua Pros today to schedule a pond remodeling.

Give us a call or fill out the contact form—we’ll take a look before things get worse.

What Are the Signs Your Backyard Pond Needs Repair?

Catching backyard pond repair signs early can make the difference between a quick fix and a full-blown renovation.

If you live in Brentwood or surrounding areas like Discovery Bay or Benicia, here are some key signs your pond needs attention.

Visual Red Flags

• Murky water or discolored water that stays cloudy even after regular maintenance often points to a filtration system issue or excessive nutrients.
• Visible cracks in the pond’s edge or hardscape may signal structural damage or a failing pond liner. Concrete ponds can also crack and leach lime into your pond, which is why we install liners vs. concrete for our ponds.
• Water levels dropping faster than what would be considered normal evaporation can mean leaks that need attention. Don’t wait—fix leaks early to prevent costly repairs.
• Algae overgrowth or recurring blooms, even after treatment, usually indicate nutrient imbalances, poor circulation, or outdated equipment.

Sensory Warning Signs

• A foul smell or strong foul odors could be caused by rotting debris, fish waste, or poor circulation, all of which affect your pond’s ecosystem.
• Sludge buildup visible at the bottom of the pond. This sludge can be made up of dead algae or excessive fish food and can create toxic anaerobic bacteria.
• If you notice foamy buildup or bubbling near a water feature or waterfall, this can indicate a buildup of organic matter.
• Strange humming, buzzing, or reduced flow may mean your pump, skimmer, or other gear is no longer working efficiently—a classic sign of malfunctioning equipment. Follow the link to learn why a skimmer is so important for a healthy pond.

Behavioral Clues from Fish and Plants

• Koi fish gasping at the surface or hiding all day can be a reaction to low oxygen levels or poor water quality. While it’s a common pond myth that koi can’t be kept in a pond with plants, it’s crucial to have a proportionate balance of fish and plants.
• Dead or sick fish, especially multiple in a short time, is a major red flag.
• Overgrown or rotting aquatic plants may point to water chemistry issues or a lack of light due to algae growth or sediment buildup.

Spotting these common signs early helps you protect your pond’s integrity, aquatic life, and your surrounding landscape.

Common Causes of Pond Problems

Once you recognize there’s an issue, understanding the root cause is key to solving it.

In Brentwood’s dry summers and leaf-heavy falls, these are the most common culprits behind pond repair needs.

Equipment Issues

• Malfunctioning equipment, like clogged filters or aging pumps, can disrupt circulation, leading to poor water conditions and algae growth.
• An underpowered filtration system allows debris and nutrients to build up, harming koi fish and other aquatic life. Similarly, an overpowered filtration system can also harm your fish. We specialize in installing BioFalls filtration systems made by premium pond equipment maker Aquascape. These filters use beneficial bacteria to break down pond wastes and oxygenate the water.
• Old or improperly installed gear may no longer meet the demands of your pond’s size or your current fish population.

Structural Damage

• A worn or punctured pond liner can cause hidden leaks that lead to significant water loss and further damage if left untreated.
• Soil erosion and sinking edges can crack rock borders and disrupt the pond’s shape, threatening its structural integrity.
• Poorly built or aging water features can shift over time, leading to water escaping into the surrounding soil instead of cycling properly.

Ecological Imbalance

• Excessive algae growth is usually triggered by too many nutrients in the water, often a result of overfeeding or decaying organic matter.
• Lack of circulation, shade, or oxygenation weakens the pond’s delicate balance and reduces oxygen levels, especially in summer heat.
• Without enough beneficial bacteria, fish waste and dead plant material accumulate, harming water clarity and threatening a healthy pond ecosystem.

Knowing the “why” behind your pond repair issue helps guide the right solution—whether that’s adding beneficial bacteria, improving circulation, or replacing a failed component.

When Is It Time to Remodel Your Pond?

Sometimes the issue isn’t just a quick pond repair—it’s that your pond needs a full update.

If you’re a Brentwood or Discovery Bay homeowner with an aging koi pond, here are key signs it might be time for a larger renovation.

Signs You’ve Outgrown the Original Design

• Your fish population has grown, but the pond hasn’t, leading to poor water quality and limited swimming space.
• Your layout lacks zones for aquatic plants, proper flow, or easy access for regular cleaning.
• You’re constantly working around outdated plumbing or filters that don’t suit today’s pond care standards.

Problems That Keep Coming Back

• You’re treating algae or discolored water every few weeks with no lasting results.
• Equipment seems to break down frequently, or repairs only offer short-term fixes.
• Despite your efforts, the water quality remains unstable, and your pond’s ecosystem feels off-balance.

If these sound familiar, it’s time to consider a full-scale upgrade—especially if you want to enjoy a more beautiful water feature with easy maintenance.

The Benefits of Addressing Pond Repairs Early

Waiting too long to fix minor issues can lead to water loss, damaged equipment, or even harm to your fish and aquatic plants.

Acting early pays off—especially when you care about keeping your outdoor space clean, functional, and attractive.

• Prevent further damage: A small liner tear or leak can quickly grow, leading to structural collapse or flooding.
• Maintain a healthy pond: Stable water levels, proper filtration, and timely debris removal help protect your fish, plants, and surrounding ecosystem.
• Avoid costly surprises: Tackling a pond repair now is far less expensive than a total replacement down the road.
• Keep your pond beautiful: Crystal-clear water and a thriving setup enhance your outdoor space and boost curb appeal.

Prompt repairs are about more than just function—they protect the well-being of your entire living ecosystem.

Proactive Pond Maintenance Tips

The best way to avoid major repairs is simple: keep up with regular maintenance.

Whether you’re in Benicia or San Mateo, a little effort goes a long way in keeping your pond healthy and running smoothly.

Seasonal Maintenance Routines

• Spring: Clean out debris, restart pumps, check for winter damage, and trim back pond plants.
• Summer: Watch water levels, clear surface debris, and monitor algae growth.
• Fall: Net the pond to catch falling leaves, prune plants, and prep the pond liner for cooler temps.
• Winter: Continue pond care as needed. We often do cleanouts in the winter in the East Bay area since we don’t have to deal with ice and fish are less likely to be stressed by cleaning if they are already dormant.

Regular Checks to Catch Issues Early

• Inspect for leaks, odd smells, or strange noises once a week.
• Check your filtration system and pump performance monthly.
• Test water quality quarterly to ensure safe conditions for fish and aquatic plants.

Staying consistent with small tasks helps pond owners avoid big problems—and ensures your pond remains a relaxing, reliable part of your landscape.

Don’t Let Your Pond Fall Apart—Let California Aqua Pros Bring It Back to Life

Now that you know how to spot issues early and what they mean for your pond’s health, you’re better prepared to protect your fish, your plants, and your investment.

Staying ahead of leaks, poor filtration, or algae trouble helps keep your outdoor space clean, safe, and looking great year-round.

If it’s time for expert help, California Aqua Pros has been remodeling and repairing ponds since 1993.

Our pond experts know exactly how to restore balance, fix structural problems, and turn your aging pond into a thriving, beautiful water feature.

 

Key Points

• Build a koi pond in the East Bay by selecting a shaded, level location, digging at least 3 feet deep, and installing a liner, skimmer, and BioFalls filter system.
• Add aquatic plants on shallow shelves and acclimate koi fish gradually to maintain a balanced ecosystem.
• Maintain your pond by feeding koi and cleaning filters and debris regularly.

Make a Splash in Your Backyard Paradise

Ever stare at your backyard and think, “This space could really use something special”?

Or dream of relaxing to the sound of trickling water while colorful koi swim just a few feet away?

In this beginner’s guide, you’ll learn exactly how to build a koi pond in the East Bay—from planning and digging to installing pumps, plants, and fish.

We’ll walk you through every step with clear, simple directions so you feel confident from start to finish.

By the time you’re done reading, you’ll know how to create a peaceful pond construction that looks great and works great, too.

Ready to transform your yard into a living, breathing oasis?

Call California Aqua Pros or fill out the contact form today—we’ll help bring your vision to life.

Understanding Koi Ponds

If you’re learning how to build a koi pond in the East Bay, it’s essential to understand what sets a koi pond apart from a basic backyard water feature.

More than just a decorative addition, a properly designed pond creates a healthy environment for koi fish to thrive.

What Is a Koi Pond?

A koi pond is a purpose-built aquatic space designed to support the health, growth, and beauty of koi fish.

Unlike a basic garden pond, it requires intentional depth, a reliable filtration system, and clean pond water circulation to support fish life long-term.

Key features of a koi pond include:

• A deeper pond (usually at least 3 feet) to protect fish from East Bay temperature swings and predators.
• A proper filtration setup that keeps the water clean by removing waste and encouraging beneficial bacteria. We specialize in installing Aquascape BioFalls biological filters that work with a skimmer and beneficial bacteria to keep water naturally clear.
• A high-quality pond liner, often a flexible pond liner, to hold water securely while shaping your pond.
• Sufficient surface area for gas exchange, which allows oxygen to reach the fish and supports water clarity.

Benefits of a Koi Pond

Whether you’re enhancing your yard in Concord or adding serenity to a backyard in Walnut Creek, a beautiful koi pond offers more than just good looks:

• Aesthetic Enhancement: Adds movement, color, and peaceful water features to your landscape.
• Ecosystem Support: Attracts dragonflies, frogs, butterflies, birds, and helps balance your outdoor fish population.
• Personal Enjoyment: Caring for koi fish and aquatic plants can become a calming, year-round hobby.

By understanding the unique needs of koi and their environment, you’ll set yourself up for success before you ever dig that first hole or unroll your liner.

Let’s move on to the tools and materials you’ll need to get started.

Tools and Materials

Before you start digging, make sure you’ve got everything lined up.

Building a koi pond in your backyard takes more than just enthusiasm—it takes the right tools, durable materials, and a good plan.

Here’s what East Bay homeowners should have on hand.

Tools

These tools will make your project smoother and safer:

• Shovel: For excavation and shaping the pond.
• Pickaxe and Jackhammers: Helps break through tough East Bay clay and rocks.
• Wheelbarrow: Move rocks, gravel, and soil with ease.
• Level: Keeps shelves and pond edges even for proper water balance.
• Tape Measure: Measure pond length, width, and depth accurately.
• Utility Knife: Essential for cutting your flexible liner and tubing.
• Garden Hose: Outline your pond shape or fill it once built.
• Spray Paint: Great for marking where to dig or place key features.
• Rubber Mallet: Adjust and position rocks without cracking them.
• Channel Locks:Tighten and secure plumbing connections.
• Screwdrivers: Attach various pond components.
• Wirecutters and Nuts: Connect electrical components.
• Primer and Glue: Install PVC piping and slip fittings.

Materials

The right materials ensure your pond functions well and lasts:

• Flexible Pond Liner: A strong, weather-resistant liner to hold water in place. Here at Cal Aqua Pros, we use a premium 45 mil EPDM (Ethylene Propylene Diene Monomer) liner to ensure long-term durability.
  • *See below for a quick overview of different pond liner materials and why EDPM is the best option for East Bay pond owners. (Note: Mils are how liner thicknesses are measured. 1 mil is equal to a thousandth of an inch, so 45 mil is equivalent to .045 inches).
• Underlayment Fabric: Protects the liner from sharp objects underground.
• Pond Pump: Keeps water moving—choose the right pump size for your pond volume.
• Mechanical Skimmer: Collects floating debris like leaves. Follow the link to learn why a skimmer is so important.
• Biological Filter (BioFalls): Breaks down fish waste and improves water clarity.
• Flexible Tubing: Carries water from your pump to the filter or waterfall.
• Hose Clamps: Secure tubing connections and prevent leaks.
• Rocks and Boulders: Frame the pond edges and support a natural look.
• Gravel: Covers the bottom of your pond, supports plants, and nurtures beneficial bacteria.
• Aquatic Plants: Help control algae, provide shade, and improve oxygen levels.
• Dechlorinator: Neutralizes chlorine in tap water before adding koi.
• Pond Foam Sealant: Seals gaps between rocks and directs water flow.
• Fish Food: Choose a high-quality blend designed for koi.

* Below are the 5 main types of pond liner materials available and their qualities:

1. EPDM (Ethylene Propylene Diene Monomer) – Strong, flexible, and puncture-resistant, we believe EPDM is the best option for East Bay ponds. We use a 45 mil thick liner to ensure durability.
2. HDPE (High-Density Polyethylene) – Strong, but difficult to repair
3. PVC (Polyvinyl Chloride) – Budget-friendly but vulnerable to UV (ultraviolet) exposure
4. RPE (Reinforced Polyethylene) – Strong, but a lack of flexibility makes it difficult for ponds with lots of contours
5. Concrete – Expensive and prone to cracking, especially when done incorrectly

Step-by-Step Construction Guide

Let’s walk through the actual build process step-by-step.

1. Planning and Design

Before you dig a single inch of your yard, take time to plan your koi pond carefully.

East Bay backyards vary widely, and where you place your pond will directly impact its water quality, fish health, and long-term maintenance.

• Pick the right spot: Ideally, you should choose a level area with partial shade to reduce water temperature spikes and help control algae growth. A professional pond builder can help you integrate your water feature into more complex landscapes.
• Check for underground utilities: Always call before you dig to avoid pipes or cables.
• Determine your planned depth: For a healthy koi fish habitat, aim for at least 3 feet of depth to protect against predators and temperature swings.
• Visualize your design: Consider adding a waterfall, plants, and curves to give your pond a more natural shape.

2. Marking the Pond Outline

Once you’ve chosen a location, it’s time to mark out your future backyard koi pond.

• Use a garden hose to lay out the general shape and flow of the pond.
• For sharper edges or more precise measurements, grab some spray paint and outline your design directly on the ground.
• Think in layers: include shallow shelf areas for plants, and a deeper zone for your koi to gather and rest.

3. Excavation

With your shape locked in, it’s time to break ground and bring your design to life.

• Dig your hole in stages, starting with the outer shape and working your way down to deeper zones.
• Include shelves at multiple levels (e.g., 6″, 12″, and 24–36″) to support aquatic plants and give your koi fish space to swim at different depths.
• Keep sides slightly sloped to prevent soil collapse and allow smooth water flow.
• Save your dirt in a wheelbarrow—you’ll use it later to build up edges or berms behind your waterfall.

4. Installing Underlayment and Liner

Your pond liner is what holds the water in place, so don’t rush this step.

• Lay down underlayment fabric first to cushion the liner and protect it from rocks or roots.
• Next, roll out your flexible pond liner, making sure it covers the entire hole with at least 1–2 feet of overlap around the edges. We use a premium EDPM liner, but some pond contractors may use concrete. Follow the link to learn why we are on the liner side of the liner vs. concrete debate.
• Press the liner into corners and creases as you go, smoothing it out with your hands or feet—avoid sharp tools here.
• Let the liner rest in the sun for a bit—it will soften and mold more easily into shape.

5. Positioning Skimmer and BioFalls

Now it’s time to install the heart of your filtration system—the skimmer and BioFalls.

These two components help your koi pond stay clear and balanced year-round in the East Bay climate.

• Skimmer: Place it at the edge of the pond to capture floating debris like leaves before it sinks. This helps reduce sludge and boosts water quality.
• BioFalls: Install on the opposite side of the skimmer. It acts as a biological filter, promoting the growth of beneficial bacteria that break down fish waste and organic matter.
• Tip: For the most natural flow, the waterfall should return water downhill or across from the skimmer.

This setup ensures your backyard koi pond stays cleaner with less effort—ideal for easy maintenance.

6. Adding Rocks and Gravel

To make your pond look natural and function well, you’ll need to add rocks and gravel across various surfaces.

This isn’t just about style—it’s about long-term performance and the health of your fish.

• Rocks: Use large rocks around the edge to anchor your liner and blend your pond into the surrounding garden.
• Gravel: Spread small gravel across the pond bottom and plant shelves. This provides surface area for beneficial bacteria and gives your pond a clean, finished look.
• Safety tip: Avoid sharp stones near the liner—they can cause tears or punctures.

This layer of stone not only keeps things tidy but also supports biological filtration, helping you maintain a healthier aquatic environment.

7. Installing Pump and Plumbing

Your pump moves water through your filters and waterfall, keeping your ecosystem balanced and your pond water well-oxygenated.

Choose a pump that matches your pond’s size and elevation change.

• Place the pump inside the skimmer so it stays hidden and protected.
• Connect tubing from the pump to the BioFalls. Use secure fittings and hose clamps to prevent leaks.
• Check flow: Water should cycle through the entire pond at least once every hour for optimal filtration and oxygen flow.

A good pump setup is what keeps a beautiful koi pond looking fresh and thriving with life.

8. Filling the Pond

With all your components in place, it’s finally time to add water and bring your East Bay backyard pond to life.

• Slowly add water with a garden hose, watching the liner to ensure it molds smoothly into all corners and shelves.
• As it fills, adjust rocks and edges to keep the liner from shifting.
• Use a dechlorinator before introducing koi—this step is critical to protect your new fish from harmful chemicals.

9. Introducing Aquatic Plants

Adding plants to your koi pond isn’t just about beauty—it plays a vital role in supporting water balance, preventing algae growth, and giving your koi places to rest and hide.

• Shallow shelves: Place potted aquatic plants in these areas to help them thrive without being uprooted.
• Floating plants: Species like water lilies and water hyacinths help shade the pond and reduce algae by blocking direct sunlight.
• Oxygenators: Submerged plants such as anacharis increase oxygen levels and reduce excess nutrients that algae feed on.

In East Bay gardens, these plants not only look great but help you maintain cleaner, clearer pond water with less effort.

10. Acclimating and Adding Koi Fish

Your backyard koi pond is almost complete—but before you add your fish, make sure the water is ready and your setup is stable.

• Acclimate slowly: Float the transport bag in the pond for 15–20 minutes to match temperatures.
• Add pond water gradually: Introduce small amounts of pond water into the bag to help your koi fish adjust to the new chemistry.
• Release gently: Once acclimated, let your koi swim out on their own.

Avoid overstocking—aim for fewer fish with room to grow.

A well-balanced pond supports long-term fish health and reduces the load on your filters.

11. Regular Maintenance

To keep your East Bay koi pond looking great and functioning well year-round, consistent care is key.

Regular maintenance helps prevent issues before they start and keeps your koi healthy.

• Feeding: Offer high-quality food once per day (maximum) during warm seasons. While fish food is fine as an occasional treat, we recommend letting your fish feed primarily from naturally occurring food sources in the pond ecosystem. In winter, reduce or stop feeding entirely depending on temperatures.
• Check filters: Clean your skimmer and biological filters routinely to prevent clogging.
• Monitor water: You may want to occasionally test for pH, ammonia, and nitrate if you think there might be imbalances, but it’s a pond myth that that your water must be tested daily.
• Remove debris: You may need to scoop out leaves and excess plant matter to stop it from sinking and turning into sludge.

Following a simple routine keeps your pond clear, your fish thriving, and your backyard pond the highlight of your landscape.

Ready to Bring Your Dream Koi Pond to Life? California Aqua Pros Can Help

You now know exactly how to build a koi pond from scratch—from planning and digging to adding fish and water features that transform your backyard into a peaceful retreat.

With the right tools, plants, and setup, maintaining a beautiful koi pond in the East Bay is more achievable than ever.

If you’d rather skip the shovel and let pros handle the hard work, the pond builders at California Aqua Pros are ready to design and install a custom koi pond that fits your yard, your style, and your goals.