Koi fish ponds are beautiful, soothing water features increasingly popular in American backyards. You can install a mid-sized model for $5,100 to $15,900, and the maintenance is about $1,000 to $2,000 per year.
The cost of a koi pond varies widely depending on size, materials, and additions. You can set up a small pond for as low as $500, while large koi ponds with premium features can cost up to $80,000.
This price guide talks about the following:
- Average Koi Pond Costs
- Koi Pond Cost Estimator by Size
- Other Factors That Affect Cost
- Related Services
- Cost by Location
- FAQ
Average Koi Pond Costs in 2025
| National Average Cost | $10,500 |
| Typical Price Range | $5,100 – $15,900 |
| Extreme Low-End Cost | $500 |
| Extreme High-End Cost | $80,000 |
Most koi ponds cost between $5,100 to $15,900 to install, with a nationwide average of $10,500. The total cost of koi pond construction varies with size, materials, and add-on features, so you can adjust it to fit your budget and needs.
If you’re looking for a low-cost pond project with a tight budget, consider the following:
- Go for a small pond, about 7 feet by 8 feet and 4 feet deep.
- Install it DIY using a prefabricated liner.
- Use reclaimed stones for edging.
- Opt for a minimalist design.
- Buy domestic, small koi from local pet shops.
To make sure you don’t drift toward an expensive koi pond, keep in mind that prices rise fast for:
- Large pond sizes and atypical shapes.
- Concrete liners professionally installed.
- Imported koi fish, rare specimens, or fish bought at a mature age.
- Extra landscaping elements such as bridges, floating steps, statues, etc.
Since the size of the pond is a significant cost factor, make sure you choose the proper one for your budget and the number of koi fish you want to raise.
Koi Pond Cost Estimator by Size
A small koi pond of 7 feet by 8 feet can be installed for $2,800 to $7,280. If you have room in your backyard for a larger pond covering an area of 21 x 26 feet or more, expect a koi pond price range starting at over $27,000.
| Project Size | Average overall cost |
| 7 x 8 feet | $2,800 to $7,280 |
| 11 x 16 feet | $8,800 to $22,880 |
| 21 x 26 feet | $27,300 to $70,980 |
The price for building a koi pond also varies with depth. A koi fish pond should be at least 4 feet deep for most koi. If you keep jumbo koi, plan for a depth of 6 to 8 feet.
Note: Experts recommend a pond large enough to keep at least 1,000 gallons of water. This volume is enough to raise 4 koi fish to maturity comfortably.
Other Factors That Affect Cost
The pond’s size impacts the cost of installing a koi fish pond, but there are other cost factors, such as:
- Excavation services
- Pond liner
- Filtration system
- Water pump
- Waterfalls and returning jets
- Edging
- Koi fish price
Excavation Services for a Backyard Pond
It costs $60 to $200 per cubic yard to dig a suitable cavity for a garden pond or swimming pool. Prices are higher for:
- Irregularly shaped designs
- Digging in clay or rocky soil
- Manual excavation (when powered equipment can’t enter your yard).
While you plan to dig, check if you need a permit for disturbing ground in your backyard. Depending on project size and location, such permits cost about $150 to $485.
If the yard is sloped, you’ll also require grading and leveling services, for which you can expect to pay $40 to $180 per hour.
Pond Liner
The liner covers the walls and bottom of the pond, keeping water in, and costs $0.30 to $114 per square foot depending on the material. As you can see, the pond liner material you choose can make a HUGE difference in your budget.
RPE and HDPE liners are the most affordable, while concrete is the most expensive. PVC can be toxic for koi fish, so it’s better to avoid it.
Here are some prices for the most popular koi pond liner materials.
| Pond Liner Material | Average Cost Per Sq. Ft. |
| HDPE (High-Density Polyethylene) | $0.30 to $0.70 |
| RPE (Reinforced Polyethylene) | $0.45 to $1.65 |
| Non-toxic EPDM | $0.65 to $2.30 |
| HDPE pre-formed tank | $3.40 to $7.40 |
| Fiberglass pre-formed tank | $10 to $80 |
| Concrete | $64 to $114 |
Filtration System
Most koi pond filters available online include mechanical and biological filters. Such a device costs about $150 to $1,300. Its capacity and price depend on the volume of water it needs to filter. To calculate what size filter you need, multiply the pond volume by 1.5. See below for some estimated costs for small, medium, and large ponds.
| Pond Size | Filter Capacity | Filter System Cost |
| 7 x 8 feet | 2,520 | $150 to $400 |
| 11×16 feet | 7,920 | $700 to $900 |
| 26×26 feet | 30,420 | $2,000 to $5,000 |
Koi ponds also need a bottom drain, a skimmer, and a UV light to function correctly:
- A pond skimmer costs $100 to $700 and collects large debris floating above the pond, like leaves and twigs. What falls to the base of the pond is either sucked in by the bottom drain, or you’ll have to collect it with a manual skimmer.
- Bottom drains are available as kits for $170 to $255, not including the pipes and installation cost.
- Ultraviolet lights cost $55 to $600 per item and treat the water after filtering before returning to the pond. They prevent algae blooms and keep water crystal-clear.
Water Pump
For small to medium ponds, a circulation pump costs $50 to $500. More powerful models are priced at $1,000 to $2,000. Look for a water pump that can circulate the entire pond volume at least once every three hours.
Some homeowners also install auto-fill valves, costing $30 to $100 per item. They automatically add water to the koi pond when the volume decreases due to evaporation or filter cleaning.
Waterfalls and Returning Jets
A waterfall costs about $500 to $2,500 and adds a natural look and soothing trickling sound to the pond. It’s typically paired with a few returning jets, costing $10 to $50 per item.
These add-ons return the water to the backyard pond after filtration and UV treatment. They also add oxygen and create beautiful water currents for fish to swim around in. You can complete the mix or replace a waterfall or jet with a water fountain for an average price of $1,100 to $4,300.
| Water agitators | Price per item |
| Waterfall | $500 to $2,500 |
| Returning Jet | $10 to $50 |
| Water fountain | $1,100 to $4,300 |
Koi Pond Edging
Depending on size, shape, and chosen materials, you’ll spend about $700 to $1,750 to add edging to your pond. The most popular choice is rockery (gravel, rocks, boulders), but you can also use hardwood, paving stones, pebbles, mulch, and plants. Edging hides the rubber or plastic liner and helps blend the water feature into the yard’s landscape.
Koi Pond Fish
Koi fish’s name comes from the word “Nishikigoi,” meaning “brocaded carp” in Japanese. These mesmerizing creatures cost $15 to $55 per fish, depending on color, pattern, and size.
If on a tight budget, go for low-cost, domestic, small koi available from $2.55 per fish. They grow fast and have beautiful colors. Large fish and rare specimens imported from Japan can cost up to $8,000 apiece.
Some pond owners also add goldfish, catfish, orfe, largemouth bass, and other fish compatible with koi and their living requirements.
| Type of Fish | Average Cost per Fish |
| Koi fish | $15 to $55 |
| Goldfish | $1.30 – $6.85 |
| Catfish | $0.65 – $1.70 |
| Bass | $1.00 – $3.30 |
Note: Before going on vacation, consider installing an auto-feeder. It costs $100 to $125 and can take care of feeding the koi while you’re gone.
Related Services
When planning to build a koi fish pond in your backyard, consider some valuable related services such as:
Koi Pond Maintenance
A good quality koi pond is low-maintenance. You need to feed the koi fish and ensure they’re healthy and playful. Also, empty the skimmer basket when full and occasionally collect leaves and branches floating on the pond.
Professional pond maintenance services are only necessary every few months, and you should plan about $1,000 to $2,000 as an annual koi pond maintenance cost. For this price, pond caretakers provide in-depth pond cleaning and also:
- Check and clean filters
- Replace the UV lamp
- Make repairs if needed
- Prepare the pond for winter
If the fish remain in the pond during winter, you need a pond heater, costing $38 to $135 per unit. The heater keeps a small portion of the pond surface from freezing, allowing air and waste gases to get out.
Koi Pond Plants
Planting trees on the side of the pond ensures a blissful shade on hot summer days and keeps the water cooler. Depending on size and species, planting trees costs between $150 and $1,850 to install.
You can add smaller aquatic plants for $4 to $45 per seedling. The most popular koi pond plants are water hyacinths, lilies, and lettuce.
| Koi Pond Plants | Average Cost per Plant |
| Water Hyacinth | $3 |
| Water Lilly | $45 |
| Water Lettuce | $4 |
Landscape Design
If you’re not just installing a new pond but remaking the entire garden, it’s worth hiring a landscape designer. Their fee ranges from $50 to $150 per hour and adds to the cost of installation. Find a professional with experience in aquascaping projects to provide you with some koi pond design ideas.
Cost of Koi Pond Installation by Location
The cost to put in a koi fish pond varies with the local price of materials and labor. For example, landscapers in Vermont and Wyoming charge more than those in Nebraska or Kentucky.
Koi pond prices also depend on how easily you can find an experienced pond contractor. You’ll pay more if you need to hire a professional from another town, county, or state. The only way to find out exactly how much a koi pond would cost for you is to get pricing quotes from a few local contractors.
FAQ
A mid-sized koi pond of 11 feet by 16 feet, suitable for a regular backyard, costs between $8,800 to $22,880 to install. Pricing varies with size, materials, and location.
Technically, you can, especially if using a pond kit for a small pond. The DIY koi pond cost can be as low as $500. But it’s not always the best idea. Many details need to be in sync to create an ecosystem pond that is comfortable, healthy for koi fish, and easy to maintain. It’s best to work with a professional pond builder or at least consult with one before starting a DIY pond project.
However, with the right research, you can build a great koi pond on your own! See our guide on how to build a small backyard pond to get started.
On average, the most expensive type of koi fish is the Kōhaku variety. While small fish can be bought for less than $100, adults cost thousands of dollars, and the most valuable has been sold for $1.8 million.
Koi ponds are stunning water features with a unique soothing effect. They beautify any outdoor space and increase property value. All their benefits say it’s worth installing a koi pond in your own backyard, but only if you’re committed to taking care of the fish. Koi need at least a few minutes a day from you and have an average lifespan of 20 years.
It depends on their number. Technically, you need at least 250 gallons for a mature Japanese koi 20 to 25 inches long. So, 1,000 gallons of water can be enough for 4 mature koi fish. If you have jumbo fish growing up to 36 inches in length, 1,000 gallons will be enough only for 3 adult fish.
Yes, but only after dechlorinating it. Chlorine and chloramine are toxic for koi fish and aquatic life in general. Before exposing the fish to tap water, you must eliminate these substances.
Learn more from our answers to the 10 most common questions homeowners have before installing a koi pond.
Final Thoughts
It costs $5,100 to $15,900 to have a koi pond installed in your backyard. With playful, colored koi fish, such a water feature transforms your outdoor space into a relaxing and welcoming environment.
Pricing varies with size, materials, and landscape features, so you can adjust the investment to suit your plans. Contact a local landscape expert and see what a koi pond would look like for your available space and budget.
Main Photo by: Wonderlane / Flickr / CC BY 2.0
