Should I Cover My Pool When It Rains?

Backyard pool in rainstorm uncovered

Though pools are most often enjoyed on the bright sunny days of summer, there are also days where it’s cloudy and rainy.  Oftentimes we are asked what you should do with your pool when it rains? Questions like, should I cover my pool when it rains? And the question of does my automatic cover need to be closed when it rains comes up from time to time.

Should I Cover My Pool When It Rains?

You may think it’s best to keep the cover closed when it rains, to keep out the rainwater.  After all, if your pool is full of water already, who wants the additional water in the pool?  If you have your automatic cover closed however, you’ll need to install the cover pump also.  This is the small sump pump which is placed on top of the automatic cover whenever it’s closed.  If you live in a place like Arizona, you may not use a cover pump since rainfall is infrequent.  But in damp climates, the cover pump is a part of life.  

The cover pump can be a bit of a hassle.  Especially if you forget to plug it in, or you forget to put it on the pool cover in the first place.  Then, you go out to your pool after a rainstorm expecting to retract the cover only to find you have a few inches of water on top of the cover. To make matters worse, the cover won’t budge until you pump the water off.  This can take an hour or two for the small cover pump to pump off the water. All the while you and your guests are waiting by the pool for the cover to be opened. 

To avoid this circumstance, you could just open the pool cover whenever it rains.  Yes, you’ll have to keep an eye on the water level, and make sure it’s not getting overfilled. However, you can drain water out of the pool easy enough using the hose bib installed at your pool equipment.  

Should I Cover My Pool When It Rains Shown In Backyard With Rainstorm and Pool Uncovered

Cons Of Leaving Your Pool Open During Rain

One of the cons of leaving your pool cover open when it rains is the fact that the rainwater will cool your pool.  Generally speaking, rain is going to be colder than your preferred water temperature. Therefore, the rainwater will lower the pool temperature.  This is something you’ll have to weigh if you are heating your pool.  By opening the cover and leaving the pool open in the first place you will be increasing the fuel burned or electricity consumed to keep the pool heated, and then there’s the temperature of the rain itself.

Open Or Closed: Heating Costs Vs. Cover Pump Effort

In general, it’s a balance between heating costs and cover-pump frustration.  Sometimes it helps to add a second cover pump to your pool if you have trouble getting all the water to pump off the surface of the cover.  In our experience this is especially true of pools larger than 18 x 36.  In some cases, we have had clients get so frustrated with the cover pump aspect of pool ownership they just leave the pool open all the time. At that point, they no longer use the automatic cover.

If you have had a dry summer, and you don’t have an automatic water level control system in your pool, you definitely should leave the pool open during the rain to refill the pool.  Tap water is going to be just as cold or colder than the rainwater. You may as well use the water nature provides to refill the pool.  

Should I Cover My Pool When It Rains Summary

Ultimately, there is nothing wrong with leaving your pool cover open during the rain. There are only two considerations to factor in to make your decision. First, there is the safety aspect of leaving an automatic cover open. Second, the potential heat loss of leaving the cover open.  Yes, there’s the chemical dilution aspect. Although, if your pool needs to be refilled anyhow, that’s nothing to be concerned with as rainwater and hose water will have a similar effect. Sometimes the rainwater is even better quality water.