What does a koi pond pump cost to run?

Run the numbers on your own use

Change any of these and the figures update. The defaults are the typical case described above; your rate is the input that moves the answer most.

Why this is lower than the number you will see elsewhere

Almost every published answer to this question multiplies the rating on the label by the hours the appliance is switched on. For a koi pond pump that gives 1,314 kWh a year, or $241.

Continuous, and it has to be: the biological filter depends on constant flow, and stopping it for a day can kill the bacteria colony that keeps the water safe.

The arithmetic, step by step

Nothing here is hidden, so you can check it or change it. Working in the order the formula runs:

1. 150 W — what it draws while it is actually drawing. This is the rating on the plate.
2. × 100% — the share of its in-service time it is really pulling that. Continuous, and it has to be: the biological filter depends on constant flow, and stopping it for a day can kill the bacteria colony that keeps the water safe.
   That gives 150 W averaged across the hours it is on.
3. × 24 hours a day × 365 days — A pump circulating a mid-size koi pond through its filter, year round.
   150 × 24 × 365 ÷ 1,000 = 1,314 kWh a year.
4. × 18.34¢ — the US average residential rate for June 2026.
   1,314 kWh × 18.34¢ = $241 a year.

Change any assumption in the calculator above and every figure on this page moves with it. The two that matter most are your rate, which varies 4× across the country, and the hours — the duty cycle is a property of the appliance, but the hours are a property of you.

How sensitive is that number?

A single figure invites more confidence than it deserves. Here is the same appliance under assumptions either side of the default, so you can see how much of the answer is the appliance and how much is the guess about how you use it.

Everything else held at the default. The spread here is the honest error bar on the headline figure.

What it costs per hour, day and month

At 18.34¢ per kWh, the US residential average for June 2026.

The thing worth knowing

This is a 24/7/365 load that cannot be switched off without harming the fish, which makes pump efficiency the entire lever. Pump power rises roughly with the cube of flow rate, so a slightly oversized pump throttled back with a valve is a very expensive way to get the flow you want — restricting the outlet wastes energy as heat and pressure. Sizing the pump correctly, or using a variable-speed one, is worth more than anything else in a pond.

What it costs in your state

The appliance is the same everywhere; the rate is not. Running this koi pond pump costs $693 a year in Hawaii and $172 in Nevada — a difference of 4×.

Cost of running one koi pond pump for a year, by state. Residential average price, EIA June 2026.

Other water heating and pumps costs

• Hot tub

  $602 a year

  A 400-gallon tub held at 102F year round, well covered.

• Pool heat pump

  $576 a year

  Holding a residential pool at swimming temperature through an extended season.

• Electric water heater

  $499 a year

  A 50-gallon tank serving a household of three to four.

• Pool pump

  $396 a year

  A single-speed pump on an eight-hour timer through the season.

• Heat pump water heater

  $177 a year

  A 50-gallon hybrid in a basement, resistance backup rarely engaged.

• Septic aerator pump

  $112 a year

  An aerobic septic system running as intended.

Questions

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from