Custom koi pond builders for Southern California homes and properties
A koi pond that stays clear for twenty years is engineered before the first shovel hits dirt: depth, bottom drains, gravity-fed filtration, and turnover rates sized to the bioload you actually plan to keep.
What goes into a Koi Pros pond
Most pond failures we're called to fix trace back to construction shortcuts: ponds too shallow for Southern California heat, undersized pumps, skimmers with no bottom drain, or liners set on unprepared soil. We build the other way around.
- Minimum 3–4 ft depth for koi; deeper where heat load or predators call for it
- Bottom drains plumbed to gravity-fed settlement and biological filtration
- Skimmers, mid-water returns and aeration sized for full turnover every 1–2 hours
- EPDM or reinforced polyurea liner over compacted base and geotextile underlay
- Concrete and rebar shells for formal or large-volume ponds
- UV clarifiers, auto-fill and overflow, and service access for every component
Design to finished pond
We start on-site with a system assessment: sun exposure, grade, soil, existing utilities, and how many fish you want to keep. From there we produce a plan with filtration schematics, a plant and rock schedule, and a fixed scope. Construction typically runs two to six weeks depending on size and finish work, and every pond is commissioned with a water-quality baseline before fish go in.
Residential and commercial builds
We build backyard koi ponds and water gardens for homeowners, and larger display ponds for hotels, restaurants, office lobbies and HOA common areas. Commercial projects include stamped drawings where required, ADA-aware edge treatment and remote monitoring of water quality.
Signs you need koi pond help
- You want koi, not just a water feature, and the existing pond is under 3 ft deep
- You've been quoted a 'kit' pond with a skimmer and no bottom drain
- The site has grade, sun or soil issues the landscaper isn't addressing
- You're planning a commercial display pond that needs drawings and remote monitoring
What drives the cost
Volume, depth and filtration drive cost more than surface area does. A 2,000-gallon liner pond with gravity-fed filtration and a modest waterfall sits in the low five figures; a 10,000-gallon concrete pond with bead filtration, UV, auto-fill and lighting can run several multiples of that. Rockwork, access and electrical runs are the usual variables. We quote a fixed scope after the site assessment.
What this service covers
Koi pond construction sits under the wider heading of water feature construction. Clients tend to call it koi pond installation or koi pond builder; whatever the name, the work breaks down into a few distinct jobs:
Liner (EPDM / RPE) koi ponds
Flexible 45-mil EPDM or reinforced polyethylene over compacted base and geotextile underlayment; the most cost-effective build for naturalistic ponds.
Concrete and gunite koi ponds
Rebar-reinforced shells with waterproof membrane for formal shapes, raised walls, large volumes and lobby installations.
Raised and formal koi ponds
Above-grade ponds with seating-height walls, viewing windows and clean geometric edges for courtyards and patios.
Water gardens and lily ponds
Plant-forward ponds with shelves for marginals, lilies and bog filters, stocked lightly so the plants do the filtering.
Natural swimming ponds
Chemical-free swim zones paired with a planted regeneration zone and gravel biofiltration.
Indoor and lobby koi ponds
Interior ponds with engineered drainage, humidity control, remote filtration and quiet pumps for hotels, restaurants and homes.
Terms you'll hear from our technicians on this work: bottom drain, gravity-fed filtration, settlement chamber, skimmer, UV clarifier, bead filter, aeration, pond liner, underlayment, bioload, turnover rate, koi (Nishikigoi), CSLB contractor license.
Where we offer it
Routed service through Orange County, Los Angeles, San Diego County, the Inland Empire and the Coachella Valley, with construction and commercial crews traveling to Arizona.
Koi Pond Construction across Southern California and Arizona
Orange County home base, routed crews from Los Angeles to San Diego and the desert. One call, one crew, written findings.
Before and after: koi pond calls
Customer story
Victoria's raised koi pond in Garden Grove
“My son found Wes with Koi Pros online, and Wes built this above-ground fish pond for me. It's come out very nice. Every day my husband will come out here and relax and sit by the pond and enjoy the sounds and beauty of the Japanese-style koi pond Wes built for us. We also use it to water our plants with the fish waste, and our plants are very beautiful because of that. We are very pleased with Wes and his team.”
Victoria, homeowner for 30 years, Garden Grove, CA
Victoria has lived in her Garden Grove home for 30 years. Her son found Koi Pros online, and Wes built a raised, Japanese-style koi pond with a waterfall for her backyard. Her husband sits by it every day, friends come over to see it, and the fish water feeds the garden.
Pond owner tip
Free fertilizer: put your filter backwash water on the garden
“I use the wastewater from backwashing my koi pond filter to water the flowers and plants around my house throughout the year. That's why they look so beautiful! When I have time, I trim them once in a while, too. Using the pond's backwash water means I don't have to buy fertilizer.”
Victoria, Garden Grove, CA
Filter backwash carries nitrates, phosphates and fine organic solids, which is exactly what you'd buy in a bag of fertilizer. Run the backwash line to a bed or a barrel instead of the drain and you remove nutrients from the pond (less algae) and feed the landscape at the same time. Two cautions: let it settle if it's going on potted plants, and skip the garden for a few weeks after any salt or medication treatment.
Check out Koi Pros projects
Koi ponds, waterfalls and water features we've designed, built and maintain across Southern California, in one minute. The same crew handles koi ponds.
Guides on koi ponds
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Questions about koi ponds
How much does a koi pond cost in Southern California?
Properly filtered residential koi ponds generally start in the low five figures and scale with volume, rockwork and finish. We quote fixed scopes after an on-site assessment rather than by the square foot, because filtration and access drive cost more than surface area does.
How deep should a koi pond be?
At least 3 feet, and 4 feet or more in inland and desert areas. Depth stabilizes temperature, protects fish from herons and raccoons, and gives koi room to grow.
Do you handle permits?
Yes. Most residential ponds under 18 inches of retained water above grade don't require a permit, but electrical and larger commercial features often do. We handle drawings and inspections where needed.
Can you build a pond that doesn't need constant maintenance?
Bottom drains, correctly sized biological filtration and a UV clarifier are what keep maintenance down. Our ponds are designed for a monthly service visit, not weekly cleanings.