You Need to Know How Much Water is in the Pool !

In Tech Talk by Steve Donohoe1 Comment

A Rectangular-shaped Pool.

When you maintain a swimming pool – residential or commercial – you MUST know how much water is in it.   If you know how much water is the the pool, you will understand if your pool equipment is performing correctly AND you will know the correct amount of chemicals to add to the pool water.

The local health department requires that all the pool water  must pass through the filter system in a specific amount of time (The Water Turnover).  Most health departments require the water Turnover to be at least 6 hours for pools and a half  an hour (30 minutes) for spas.  If you do not know how much water is in the pool — you will never be able to calculate the required flow rate to meet the required Turnover.

Various Pool Shapes

ALL chemical additions are based on the amount of water in the pool.  If you do not know how much water is in the pool, you will ALWAYS under dose or over dose your pool — resulting in an unhealthy pool or costing YOU money!

So… how do you determine the amount of water that is in the pool? … Well, you calculate it:

Water Volume

Gallons = Surface Area   X  Average Depth  X  7.5


The pool’s water volume can also be calculated by measuring the change (in ppm) after a specific chemical is added.  Sound funky?  Well, check this out:  the research company, onBalance, came up with a chemical method to determine the water volume.  It uses their simplified dosage formulas here.  So thanks, onBalance, for another useful tool!


And Elise and I want to say, “thank you,” again, for the hospitality from PoolCorp’s crew at the Superior building in Anaheim.  And a special thanks goes to John and Tony for helping us carry our equipment and supplies upstairs — guys, you ROCK!


  1. Steve,
    The funniest answer I received to this question in a call from a customer:
    Me- “Sir, do you know how much water there is in your pool?”
    Customer- “Not really sure, but it is smaller than my neighbors pool and he’s not having any trouble”.
    See ya

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.