I have a situation that was described on a previously abandoned thread that never produced a good solution. I have owned a home with an inground pool in the desert of CA for 2 years. I have not filled my pool once this summer and the water level remains the same or rises - - no cracks in the plaster - no leaks in the fill valve - not sure where the water comes from. Can someone tell me if this theory is plausible- since it is hot during the day and cool at night the pool releases heat at night and gets cold. During the next day, humid hot air hits the cold pool surface and cools down. When the humid hot air cools, it no longer has the capacity to hold so much water so condensation forms, filling the pool. Is that crazy?
Pool filling itself :)
- Thread starter JakeStelly
- Start date
- Status
- Feb 6, 2015
- 6,015
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome toTFP 
If you never manually add water to your pool, you have an auto-fill plumbed in - or someone is adding it without you knowing.
If you never manually add water to your pool, you have an auto-fill plumbed in - or someone is adding it without you knowing.
That's because there is NO good solution. It is just nonsense to think water appears without a source. ....and condensation is not it, either. Evaporation FAR outweighs any chance of condensation adding to a pool.
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- Jul 3, 2013
- 9,028
- Pool Size
- 15000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-40
you say you have an auto fill, that is where the water is coming from so not really sure what your question is other than a head scratcher 
Something is filling that. Are you on city or well water? If city water, has your water usage been lower this year vs last? Check the meter, if you have a leak somewhere it will show up on the meter. Most meters have a small indicator for slow leaks, you can also ensure you have no water usage and check the meter like 10-15 minutes apart.
Or if you go on a trip for a few days, shut your main water valve off, see if the pool level has dropped when you get back.
Or if you go on a trip for a few days, shut your main water valve off, see if the pool level has dropped when you get back.
This was the first year I never added any water during the year. My water source is well-timed rains.
"no leaks in the fill valve - not sure where the water comes from"
You answered your own question...the auto fill valve is adding water, just like your toilet adds water to the tank...
And, Dave S is spot on, evaporation far exceeds an minute forms of condensation...
You answered your own question...the auto fill valve is adding water, just like your toilet adds water to the tank...
And, Dave S is spot on, evaporation far exceeds an minute forms of condensation...
Thanks guys and gals! I have a manual fill valve but no auto fill valve. I have to manually turn the spigot on like a hose... which I have not done all year and it is not leaking. My water bill is lower this year since I am not putting water in. I have checked my water usage report when I knew nobody was using water all day - no leak. Could it be ground water seeping in through the plaster even if I don't see cracks?
No. The seepage through a pool wall is microscopic at best and water can't flow uphill.
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I can tell you that there are many factors to consider. The temperature differences of the day, cloud cover, heat, humidity, rain, wind..... all of them working together or against each other. I had 8 completely different years with my pool. Sometimes month to month saw a drastic change, or even week to week, other times it was for the whole season.
One things for sure, If there was a way to invent free water, 20% of the world wouldn’t have to go without.
One things for sure, If there was a way to invent free water, 20% of the world wouldn’t have to go without.
Just for grins...go buy a 5gal plastic bucket at one of the big box stores. Take a black sharpie and make a line 1” from the top. Fill the bucket up to the line. Then observe both pool water line & bucket line and report back in one month...
Have you been extra Smokey from all the CA fires this year ? That could be another piece of the puzzle.
Desert Dog
Silver Supporter
I'm up the hill from Santee. Smoke has not been a factor. My pool does not make any water. Would love to come see it. I'm 20 minutes away.
Would love to come see it. I'm 20 minutes away. 
- Jul 17, 2019
- 3,694
- Pool Size
- 13000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
What kind of filter do you have and are you connected to the city sewer? Do you have an overflow drain on the pool and is that connected to deck drains or gutters?
I have never heard of a sewer or overflow backing up into a pool and it is highly unlikely to occur.. but its more plausible than water magically appearing.
I have never heard of a sewer or overflow backing up into a pool and it is highly unlikely to occur.. but its more plausible than water magically appearing.
Thank you guys for feeling the need to make me aware that magical water creation is not real - can't get anything by you. The bucket test is a great idea - thanks TSTEX!
I hear you but you are asking us to solve something that has NO solution. What you are describing can't exist so naturally you will get answers of equal value.
This is often where the hard feelings and name calling gets started so I am closing the thread
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