Pond Pump Sizing

Pond pump sizing is relatively straightforward.

For any pond greater than 1000 gallons, use an external pond pump for best efficiency.

For any pond less than 1000 gallons an external pump is preferred but a submersible pump will do the job.

How Big

But how big does it have to be?

Your pump should move the total volume of your pond in one hour. So if your pond is 500 gallons, the pump should be able to move 500 gallons of water per hour. If it is 5000 gallons, the pond pump sizing should be such that the pump is rated for 5000 gallons an hour. Or you have two 2500 gallon rated pumps. The rule of thumb is that for good operation, your pump turns the total water volume over every hour.


So how do I calculate how big my pond really is?

Funny you should ask. Here’s the math.

Pond size in gallons= Length x Width x Depth x 7.5

So if your pond is 5 feet long by 3 feet wide and 2 feet deep. The math goes 5 X 3 X 2 X 7.5 = 225 (The pump should be rated for 225 gallons per hour)

Circular Pond Pump Sizing

For circular ponds, multiply 3.14 x 1/2 diameter x 1/2 diameter x depth x 7.5

So this should do basic pond pump decisions. You now know how to roughly size the pump for a simple job. Other factors such as "head" etc. are included on the main pump page.

You can find pond pump sizing and pricing here