Rain in inches = number of gallons formula

[jimbethesda]

It’s showtime! Acid wash is happening now, then we will start filling it up. We are expecting about .5” of rain tonight. Is there a formula I can use to plug in the amount of rain and my pool surface area of 540 sq ft to determine how many gallons of rain goes into my pool? I’m trying to get an accurate estimate of how many gallons my pool holds. I’ll take a picture of my water meter, but this rain will have some of an impact.

Thanks.

 

[jimbethesda]

I found this calculator. Does this look right?

Rainfall calculator (English units)<br>How much water falls during a storm? USGS Water Science School

 

[Donldson]

1 sq ft = 144 sq inches. 540x144 = 77,760 sq inches of surface area. 77,760 sq inches x 0.5 = 38,880 cubic inches of water. 38,880 cubic inches of water is 168.3 gallons.

That's why we remind people that rain has little impact on water chemistry, unless it is a huge storm with several inches of water rain contributes a very small percentage to the total water volume of a pool.

 

[jimbethesda]

1 sq ft = 144 sq inches. 540x144 = 77,760 sq inches of surface area. 77,760 sq inches x 0.5 = 38,880 cubic inches of water. 38,880 cubic inches of water is 168.3 gallons.

That's why we remind people that rain has little impact on water chemistry, unless it is a huge storm with several inches of water rain contributes a very small percentage to the total water volume of a pool.

Thanks!

 

[santacruzpool]

That's why we remind people that rain has little impact on water chemistry, unless it is a huge storm with several inches of water rain contributes a very small percentage to the total water volume of a pool.

In California our rain is typically concentrated in 3 months of the whole year it seems - we have received over 16" in February and 9" in March already. One year we received 40" of rain at our pool. That will almost re-fill my entire pool! This year we are approaching 36" since October, and most of it is from the last several weeks.

At one point this winter I opened the cover on the pool for a few storms and added about 10-12" of rain in it to dilute my CH down from 375 to 300 or so. I had to add a bag of salt afterwards to bump that back up, and I will be adding some CYA in the next few weeks to get it back to 40.