How Many Gallons of Water in a Pond?

How are  gallons of water in a pond calculated?  To find the gallons of water in a pond, we use the calculation of length x width x 80% x average depth x 7.48.  Why 80%?  Ponds are usually not square, but about 80% of a square. You may have a round pond that is shaped more like a kidney bean, an off-centered oval or a natural flexible shape like the pond pictured here.

What is with the 7.48%?  There are 7.48 gallons of water in a cubic square foot.

(L x W x 80%) x average depth x 7.48 = gallons in a pond.

So for a 10 x 8′ pond with an average depth of 2 ½ feet, it would look like this:

10 x 8 x .80 = 64.  64 x 2.5 x 7.48= 1,196.8 gallons.

Why it is important to know the gallons of water in your backyard pond?

When you purchase beneficial bacteria, algaecide or other products, the directions will specify the amount to put in based on the gallons of water in the pond.  While it may not seem like a big deal, overdosing a pond with a product could cause fish and plants to die.  Always know the gallons of water in your pond for the safe addition of products to help your pond stay in balance.  Check out Ponds 101 for more information and topics about ponds!