How To Figure Pond Water Volume

It’s Very Important To Know Your Pond’s Gallonage

How Many Gallons Of Water Does Your Garden Pond Hold? Mathematical Formulas To Help You

If you plan on introducing fish into your pond, then it is very important to know as closely as possible the gallonage. In addition if you are like me, I must pay for city water. So the monthly water bill will definitely be affected if you have a garden pond, especially one where you are doing weekly water change-outs to keep your fish healthy and the water quality at optimum levels, as I do.

Not that it isn’t important to know your total pond water gallonage if you only have water plants, but it really is necessary when you get into adding swimming backyard pets. Yes … my Koi are pets to me  🙂

Want Fish? … Know Your Pond Water Volume To Help You Decrease Disease Potential

Please don’t jam too many fish into a too small garden pond. Not only are you not being fair to the fish, you are also greatly increasing the risk that they will end up sick and will probably die on you. I’ve assisted many people with pond problems AND sick fish problems … and I will tell you this …

… the #1 cause of most “HELP ME my fish are dying” calls is because of poor water quality!

Water quality is not only affected by the detritus in the pond and the amount of, or lack of, filtration available to the pond, but also on the fish load … how many fish are swimming in how many gallons of water. Then, if you have water plants added into the equation and rocks in the bottom of the pond (ROCKS!! … this is a RANT of mine for another article!!) … watch out! You are waiting for disaster to strike. That is IF you are NOT maintaining good water quality standards.

Two of the more important reasons to know your garden pond’s gallonage are:

  • For your fish’s best health, you DO need to allow a certain amount of gallons for each fish; and
  • Gallons must be known if you ever need to administer salt and/or medications

Pond Water Volume Calculations

Remember … Do Yourself & Your Fish A Favor … Figure Out Your Gallons!

Mathematical Formulas To Determine Gallons

Nothing will be as exact as a water meter that you can purchase for a pretty reasonable price (around $10 on up). It screws on to your garden hose and will reliably give you the exact gallons of water used to fill up your pond.

However, the following mathematical formulas are tried and true standbys and are quite alright to use.

**NOTE: all formulas are based on FEET and INCHES.

Rectangular or Square length x width x depth x 7.5 = gallons
Oval with straight sides length x width x depth x 6.7 = gallons
Circular diameter x diameter x depth x 5.9 = gallons


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