How to Calculate a Swimming Pool Pump Size

Government regulations require a pool pump to filter through all of the water in the pool every six hours. The necessary size of your filter will vary depending on how many gallons of water are in your pool. The following calculations are used to determine what size pump you will need to filter through the gallons in six hours.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Pool Measurements
• Pencil
• Paper
• Calculator

1. To determine how many gallons of water are in your pool, you need to know the average depth of your pool. Use the following formula:
   Shallow end depth + deep end depth / 2 = average depth

2. Using the average depth from the previous Step, use this formula to calculate pool gallons:
   Length X Width X average depth X 7.5 = total pool gallons

3. Now that you know total pool gallons, you can calculate your flow rate using the following formula:
   pool gallons / hours / 60 minutes = Gallons per minute

4. Now you know how many gallons your filter must turn over every minute to meet federal regulations. Contact your pool supplier to help you find the right size filter for your pool.

5. Once you've installed your filter, check your flow meter to make sure it is accurate and moving enough water per minute.

References

• Pool & Spa Operator Handbook, National Swimmin Pool Foundation