Cost for a Koi Pond

cost koi pond

Ballpark estimate: $500+ for a basic DIY pond kit, on up to $10,000++++ for a large, professionally installed pond

Considering investing in a koi pond? Koi are colorful Japanese fish that can add a decorative and relaxing natural element to any yard. Just keep in mind that koi ponds are typically deeper than other garden ponds and require a quality filtration system to make sure the fish remain healthy and are able to thrive.

DIY or a Professional Job?

If you are serious about do- it-yourself projects, you might want to consider building your own koi pond. While the project itself is not terribly complicated, it will require a fair amount of digging and some basic construction knowledge. Since koi are relatively large compared to the goldfish you may have encountered in a home aquarium or at the pet shop, they require a pond between three and five feet deep in order to provide adequate shelter for the fish during very cold or very hot weather. The actual depth you need will depend on your climate. You you can check to see how deep the frost line is in your area using an online source or you can call your local building inspector. Local building codes in the U.S. will reference the frost line in order to determine the minimum depth for foundations and footings. It’s important to know that your koi pond should be at least 6 to 12 inches deeper than the frost line so that the fish have room to retreat below the depth that water freezes in the ground.

You’ll also need to find out if the job requires a permit from any agency in your community. The building department or office of the building commissioner will be able to tell you what permits are required. For example, in Massachusetts any pond deeper than two feet will need a building permit and a fence to avoid accidental drowning. In addition, since the filter and pump will require electricity, an electrical permit will be required.

Koi Pond Resources

Several good sources of information are available to help you plan and build your own Koi pond if you do decide to go the DIY route. For example, offers a step-by-step guide to building your own 2,400 gallon koi pond. As with any do it yourself project, be sure you carefully consider your own skill level against the considerable knowledge that a contractor who has done this many times before will bring to the job. Assuming you will enjoy your pond for many years to come; investing some additional money up front may be worth it in the long run.

If you decide to hire a contractor, look for a company that has specific experience with Koi ponds and has a good reputation in the community. One way to help you choose a good contractor is to look for members of the Better Business Bureau (BBB) and check the BBB website to see if there are any complaints against a contractor before hiring. Another option is to ask family, friends or neighbors who have undertaken a similar project.

Questions to Get Started

Whether you decide on a DIY job or prefer to hire an expert, here are some key questions to ask yourself before you get started. For instance:

  1. How large do you want the pond to be? This depends on your budget, landscape and how many fish you plan to keep in the pond, but one rule-of-thumb suggests 250 gallons per fish.
  2. Where will you locate the pond? Partial shade is recommended but care should be taken not to exclude all sunlight, especially if you want to include plants. Shade trees may drop leaves in the pond increasing maintenance, but also provide some protection from flying predators, such as Great Blue Heron or Osprey.
  3. Will you want plants as well as fish? If so, what kind of plants? Some plants need deeper water than others, and you may also want to include a shelf along the perimeter of the pond to hold pots of shallow water plants.
  4. Who will care for the fish? Koi need to be fed during active weather (above 50 degrees) and the pond needs to be monitored for ammonia and pH levels with water changes periodically. If you don’t have time to do this yourself, you can hire a professional service to provide weekly maintenance.

Cost for a Koi Pond

Several factors will determine the expense of your pond. Here are some of the key details that will be factored into the cost:

Excavation will typically cost between $800 and $1,500 depending on the size and complexity of your pond. If you do decide to dig it yourself, remember this is a lot of digging; the savings may come at the price of a very sore back.

Liner choice can be key to the life of your pond. PVC liners are fish friendly (not all pond liners are, so be sure to ask the supplier if you are doing the job yourself) and relatively inexpensive (a 100-gallon PVC liner can be as low as $150) but may only last five years. Synthetic rubber or concrete will increase life expectancy to 20 years or more, but cost considerably more. Expect to pay $400 to $900 for a high quality rubber liner, depending on size. Concrete liners will need to be bid by a local contractor and will vary widely depending on the size of your pond and the local cost of materials.

Equipment such as the water pump, water feature, filter, ultraviolet water sanitizer, piping, valves as well as miscellaneous parts and materials (rocks, plants, etc.) will cost between $900 and $2,400+, depending on the size of the pond and quality of the equipment. Keep in mind that better built equipment will usually cost more but will also be more durable and last longer.

Electrical service to run the filtration pump, lighting and any water feature pump will need to be installed by a licensed electrician. Since water and electricity can be a lethal combination, this job is best handled by someone who has experience with ponds or pools. If you are hiring a pond contractor, use the recommended subcontractor as this will ensure a smooth and safe project completion. If you are seeking the services of an electrician on your own, follow the general rules of seeking good references and check out the BBB website before you make your choice. The electrical service will cost between $400 and $900+, depending on the amount of power required and distance from the electrical service in your home.

Note that these prices are just rough estimates for basic koi ponds. Many homeowners decide to invest even more in larger, or more elaborate koi ponds. Therefore, while you can have a good professional koi pond built for may be just a few thousand, the prices can go up to as much as $20,000 or even double this if you want to make it very large and intricate and use high-end materials.

Cost for DIY Kits

On the other hand, for a DIY installation, your best bet is to invest in a koi pond kit (you can find them online or at your local home improvement store) that comes with all of the pieces you need. A kit for a small koi pond (six feet by six feet) starts at about $500, while a kit for a large koi pond (34 feet by 34 feet) can cost $5,000 to $6,000 or more.

Cost for Koi Fish

Fish for your pond can be remarkably expensive. Individual koi that are three to five inches long cost between $30 and $325 each, depending on the quality. Larger koi in the 22 to 25-inch range will cost between $300 and $800. While koi can grow as large as 40 inches long, these fish are rarely sold, making the price a negation between owner and buyer. (Stories of fish selling for well over $10,000 may be true or may be another instance of the one that just barely got away!)

A Final Note

If you decide to include a koi pond on your property, it will very likely become something you are proud to show off to your neighbors, family, and friends. Before you dive into this project, however, take a minute to remember that the fish are alive and require care and feeding like any other pet, so in addition to the costs involved, building a koi pond also requires a regular investment of time.