How much does a koi pond cost?
Ashburn, VA

How much does a koi pond cost?

Ashburn, VA

How much does a koi pond cost?

$3,500 – $17,000average cost to build a koi pond
$600 – $3,000average yearly maintenance cost

Get free estimates for your project or view our cost guide below:

$3,500 – $17,000 average cost to build a koi pond

$600 – $3,000 average yearly maintenance cost

Get free estimates for your project or view our cost guide below:
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Tara Farmer
Written by
Tara Farmer
Edited by
Kristen Cramer
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Koi pond cost

A koi pond costs $3,500 to $17,000 on average installed, not including the fish. The cost to build a koi pond depends on the size, depth, features, and whether installed professionally or DIY.

  • Koi pond kits cost $550 to $6,100.

  • Koi pond maintenance costs $600 to $3,000 per year.

Koi pond cost
Size Typical dimensions Average cost installed
Mini 6' x 8' $3,500 – $13,000
Small 8' x 11' $6,500 – $18,000 
Medium 11' x 16' $11,000 – $27,000 
Large 15' x 20' $17,000 – $36,000
XL 21' x 26' $30,000 – $60,000 
XXL 24' x 36' $35,000 – $95,000+

*Includes professional installation.

In comparison, installing a garden pond costs $1,800 to $6,900 for a shallow 4'x6' pond with no fish.

Get free estimates from koi pond builders near you.

Average cost to install a koi pond

The following table shows the average cost to install a koi pond, not including the fish.

Average cost to install a koi pond - chart
Average cost to install a koi pond - chart
Average cost to install a koi pond
National Average Cost $10,600
Minimum Cost $450
Maximum Cost $100,000
Average Range $3,500 to $17,000

Cost data is from research and project costs reported by HomeGuide members.

Cost factors to build a koi pond

Most koi ponds have an underlayment, liner, mechanical and biological filtration system, and a pump. Features like lighting and aquatic plants are optional.

Cost factors to build a koi pond
Factor Small (8'x11')
1,900 – 3,200 gallons
Medium (11'x16')
3,900 – 6,600 gallons
Large (15'x20')
6,700 – 11,200 gallons
Excavation cost $150 – $250  $300 – $500  $500 – $800 
Underlayment cost $90 – $220 $140 – $300 $190 – $400
Liner cost $190 – $1,900 $270 – $2,600 $380 – $3,500
Pump cost $100 – $300 $250 – $700 $700 – $1,500+
Filtration system cost $100 – $500 $450 – $1,000 $850 – $2,000 
Heater cost $50 – $500 $1,000 – $2,000 $2,000 – $3,500
UV sterilizer cost $180 – $250  $200 – $350 $300 – $600
Lighting cost $50 – $200 $250 – $800  $1,000 – $3,000
Aquatic planting cost $100 - $550  $200 – $700 $300 – $1,500 
Filling the pond (garden hose) $20 – $30 $40 – $70 $70 – $110

The following factors affect the cost of building a koi pond:

  • Consultation – Some installers charge $80 to $450 for a consultation visit to assess and design the koi pond based on your location, soil type, and desired look.

  • Size, depth, & shape – Larger, deeper ponds require more excavation labor, materials, and more powerful pumps and filtration systems.

  • Extra features – Add-ons like a bridge, statue, fountain, or waterfall increase the cost.

  • Underlayment – Pond underlayment costs $0.25 to $0.40 per square foot and protects the pond liner from premature ripping or tearing.

  • Pond liner – A synthetic pond liner costs $0.30 to $0.90 per square foot for the material alone. Pond liners prevent water from seeping back into the ground.

  • Equipment

    • Pond pumps cost $100 to $1,500+ and filtration systems cost $100 to $2,000+, depending on the size and type.

    • UV sterilizers cost $180 to $500 and help to keep the water clear. A pond with total sun exposure benefits most from a UV clarifier as the sun accelerates aquatic plant growth.

    • An automatic dosing system costs $150 to $700+, depending on the brand and size. Automatic dosing treats the water regularly, reducing maintenance.

    • A pond heater costs $50 to $3,500 and helps regulate the pond temperature during winter.

  • Permits / codes / HOA – Some cities require a permit to build a pond and may require a fence around the pond. HOAs may have stricter guidelines. Contact local authorities before building.

  • Location & soil type – Rocky soil requires longer digging, increasing labor costs. Ponds built near trees typically require more upkeep due to falling debris and underground root growth.

  • Accessibility – Labor may cost more if building the pond in a difficult-to-access area of the backyard.

  • FishStocking the pond costs $10 to $60+ per koi fish, depending on the size, type, and quantity.

  • Plumbing materials – Hose piping costs $50 to $450+ before installation, depending on the required diameter and length. A bottom drain kit costs $120 to $450 and removes debris from the pond floor, reducing overall pond maintenance.

  • LaborLandscapers charge $50 to $100 per hour to install a koi pond. Installing landscaping around the pond costs $4 to $12 per square foot.

    • Electricians charge $50 to $130 per hour to install pond lighting, install an outlet, or run wiring to connect a pump or filtration system. Most electricians have a $75+ service call fee.

    • Plumbers charge $45 to $150 per hour to run a water line for the pond drain.

    • Excavation costs $2.50 to $15.00 per cubic yard to dig the pond. Most excavators charge a $500 to $800 minimum project fee.

  • EdgingRiver rocks cost $85 to $310 per yard installed around the pond. Decorative landscape curbing costs $5 to $18 per linear foot.

  • FencingFence installation costs $20 to $60 per linear foot, including labor and materials. Some cities require a fence around a pond.

  • Water Water delivery costs $200 to $1,200. Koi ponds require dechlorinated water.

Koi pond kit costs

A koi pond kit costs $550 to $6,100, depending on the size and contents.

Pond kits include everything needed to install the pond, including an underlayment, pond liner, pump, filter, skimmer, piping, and sealant.

Kits at the higher end of the range typically include extras like lighting and water treatments.

Koi pond kit prices
Kit size Average price*
6' x 8' $550 – $1,500
8' x 11' $750 – $1,800 
11' x 16' $1,300 – $2,600 
16' x 21' $2,000 – $3,500
21' x 26' $2,700 – $6,100 

*Not including installation.

  • Most pond kits are based on a 2' depth, while koi ponds require a section at least 3' to 4' deep for predator and cold weather protection.

  • Buy a larger kit than your desired pond size to ensure the liner is large enough to create the required depth.

Koi pond liner cost

A flexible koi pond liner costs $0.30 to $2.00 per square foot, depending on the material. Always confirm the liner is fish safe when installing a koi pond.

Most pond kits include a 45 mil EPDM rubber liner. EPDM rubber's strength and flexibility make it the easiest to install.

A concrete pond liner costs $50 to $130 per square foot installed and typically requires professional installation. Most concrete liners have a smooth surface and are easier to clean and maintain than flexible liners.

Koi pond liner cost
Liner type Average price per square foot Details
HDPE $0.30 – $0.60*
  • Durable but punctures easily
  • Not as flexible as rubber
Rubber / EPDM $0.75 – $2.00*
  • Flexible and durable
  • Easy to install
RPE $0.40 – $0.90*
  • More durable and puncture resistant than HDPE
  • Stiffer than other flexible liner materials
Concrete $50 – $130 installed
  • Requires professional installation
  • Permanent
  • Costly repairs if installed incorrectly
Plastic / PVC Not recommended
  • Not always fish safe
Preformed rigid liner Not recommended  
  • Limited sizes and shapes
  • Most are not deep enough for an ideal koi habitat

*Not including installation.

Koi pond installation add-on costs

Koi pond add-ons cost $50 to $5000+, depending on the feature. Some add-ons provide extra visual elements, while others help to keep the pond clean and reduce maintenance requirements.

Koi pond add-on costs
Add-on Average cost Details
Bridge $100 – $1,500 
  • Interactive and visual element
  • Increases viewing points
  • Increases access points (good for larger ponds)
Fish cave $100 – $600
  • Provides predator protection
  • Adds underwater visual element
Fountain $100 – $2,700 
  • Visual element
  • Increases aeration
  • Reduces algae growth
  • Provides white noise
Lighting $150 – $2,000
  • External, underwater, and floating options
  • Keeps predators away
  • Improves visibility and safety
  • Improves koi activity viewing
Skimmer $50 – $450 
  • Houses the pump for easy access
  • Keeps the pond surface clean
  • Prevents large debris from clogging the pump
Waterfall $500 – $5,000 
  • Visual element
  • Increases aeration
  • Reduces algae growth
  • Provides white noise

Koi fish prices

Koi fish cost $10 to $60 each on average, but some koi prices reach $10,000 or more. Koi prices depend on the size, type, color and pattern, and sex. Larger fish and brighter colors fetch higher prices. Female koi fish cost more than male koi.

Backyard garden koi pond surrounded by flowers and greenery.
Backyard garden koi pond surrounded by flowers and greenery.

Koi pond maintenance costs

Koi pond maintenance costs $600 to $3,000 per year on average, depending on the size, filtration system, and amount of debris accumulation.

Installing a pond net reduces maintenance from falling leaves and debris. Aquatic plants may increase maintenance costs due to the added organic material and filtration load.

Koi pond maintenance costs
Factor Average cost per year
Filter pad replacement $20 – $90
Spring maintenance* $300 – $1,200 
Winterizing / Fall maintenance $300 – $1,200 
Professional maintenance plan
(Weekly, bi-weekly, & monthly options)
$700 – $7,000

*Spring maintenance costs typically fall at the low end of the price range if the pond was thoroughly cleaned in the fall.

Deep clean a koi pond at least once a year:

  • Deep cleaning in the spring works well in mild and warm climates.

  • Northern regions with harsh climates do best with a deep clean in the fall as koi are more sensitive to water quality fluctuation during winter.

Additional pond maintenance costs include:

  • Feed – Total food cost depends on the quantity and whether the fish feed year-round or hibernate during winter.

  • Repairs – Pond contractors charge $100 to $300 per hour on average for a service call, plus the repair material cost. The total repair cost depends on the issue.

  • Water – Experts recommend changing out 10% to 20% of the pond water weekly.

  • Vet bills – Fish veterinarians charge $50 to $100 per office visit or $200 to $300 for home visits.

Koi pond cost to run

Running a koi pond costs $10 to $70 per month for the pump alone, depending on the size, type, wattage, and local rates.

Get free estimates from koi pond builders near you.

Lighting, a UV sanitizing system, and other optional features increase running costs.

Koi pond FAQs

Can I build a koi pond myself?

Building a koi pond DIY is possible with planning, time, and effort. Three required components are the pond itself, a mechanical and biological filtration system, and a pump.

DIY koi pond kits cost $550 to $6,100 and provide the essentials for a straightforward pond building process.

A koi pond may be above ground, in the ground, or a combination of both. Follow these steps to build an in-ground DIY koi pond:

  1. Plan – Decide on the pond size, location, and features. Check local building codes and requirements for the pond location in relation to the property and utility lines. Map out the pond shape and the pump and filtration locations.

    • Design the pond away from trees and at least 10' from a GFCI outlet.

    • The minimum recommended koi pond size is 6'L x 8'W x 4'D.

    • Consider the number and long-term growth of the koi type you plan to keep. Each adult koi requires about 250 gallons.

  2. Dig – Clear the area and dig the pond, with sides straight down and the bottom sloping to the center drain. Ensure one section is at least 4' deep. Backfill to set and level the skimmer and biological filters.

  3. Line – Line the pond with underlayment followed by a fish-safe liner. Extend the liner at least 12" beyond the pond edge. Line the pond edge with rocks to secure and hide the liner.

  4. Secure components – Attach the liner to the filtration system components with fish-safe sealant.

  5. Add water – Fill the pond with water and test it to ensure it is non-chlorinated and fish-safe.

How deep should a koi pond be?

A koi pond should be at least 4' to 5' deep in colder regions or 3' deep in mild climates. A 6' to 8' depth is best for jumbo koi.

Koi can survive in shallower ponds, but deeper ponds offer predator protection, minimize temperature fluctuations, and support koi's natural activity.

A koi pond's length should be at least 1.2 to 2 times its depth to maintain adequate water quality and a balanced ecosystem.

Does a koi pond need a waterfall?

A koi pond does not need a waterfall if it has an aeration system like a pump or air stones oxygenating the water. Still, a waterfall may be a beneficial addition as it brings oxygen into the water and circulates it, reducing algae and keeping fish healthy.

What should I do with my koi pond in the winter?

The options for managing your koi pond in the winter depend on the pond size, depth, and whether you want the koi to hibernate in the frozen pond or remain active in an indoor tank.

Keep the koi in the pond to hibernate

A pond must be at least 3' to 4' deep for koi fish to survive the winter. Koi fish are cold-blooded and hibernate at the bottom when the pond’s surface freezes.

  • Stop the water pump and filter. Stop or bypass any waterfall features.

  • Use a deicer or air pump and bubbler to keep a small hole in the ice, allowing gas exchange.

Relocate the koi to an indoor tank

Before the pond freezes, relocate the koi to a stock tank in a garage or enclosed space.

  • Hibernating koi / unheated space – Use a small filter, bubbler, and deicer to keep the water temperature below 50°F but above freezing in an unheated garage or enclosure.

  • Active koi / temperature-controlled space – Use a larger filter and bubbler to keep the koi fish active inside the home or a heated garage.

    • Cover the tank with a net to prevent the koi fish from jumping out.

    • Change the water weekly or bi-weekly, depending on the food amount and water temperature.

Getting estimates to build a koi pond

Before hiring a koi pond builder near you, remember to:

  • Get referrals from friends, neighbors, or local koi club members who have ponds.

  • Ask for references.

  • Read their reviews on HomeGuide and Google.

  • Get at least three estimates to compare.

  • Avoid going with the lowest estimate as quality may suffer.

  • If there are no local koi pond contractors in your area, hire an expert to design the build, plumbing, and filtration plans. Then, hire a local contractor or swimming pool installer to build the pond according to the specifications.

Questions to ask

  • What experience do you have building koi ponds?

  • Can you provide some local references?

  • What minimum size and depth do you recommend for koi in this climate?

  • What brand and type of pump and filtration systems do you install?

  • Does the estimate include installing a bottom drain?

  • Do I need a fence around the pond?

  • How many koi fish can I keep in this size pond?

  • What is included with the installation?

  • What add-on features do you offer?

  • Do you provide koi fish for the pond?

  • How long will the installation take?

  • What maintenance is involved after installation? Do you offer an ongoing maintenance plan?

  • Is there a warranty? If so, what does it include?

  • Do you need a permit to build the pond? If so, do you pull the permit?

  • How do I protect the koi from predators?

  • Should I bring the koi inside for the winter?