Why Doesn’t My Pool Overflow When It Rains?

inground pool with silver pool ladder and rainy conditions

This Article Was Last Updated on April 9, 2023

Backyard pools can be one of the most enjoyable pieces of your home entertaining lifestyle.  Yes, there is some maintenance you need to keep on top of here and there.  If it’s too much you can always hire a weekly pool service to handle the brunt of the work.  But what do you do when there’s a lot of rain and your pool begins to overfill?  You may find yourself asking why doesn’t my pool overflow when it rains?

Pool Overflow Consequences

Unfortunately there are some real consequences to a pool overfilling.  If you live in a place with expansive soils, like parts of Arizona and Texas, you have a real risk of doing some damage if you don’t watch your pool level.  In the worst case scenario, what can happen is once the pool overflows, water flows between the deck and the pool structure, under the deck and behind the pool.

This can cause the soil to expand. Therefore, the deck heaves, tiles pop off the side of the pool, and utility lines are damaged.  It’s very important to drain down your pool when it’s getting close to overfilling.  

In freezing climates when your pool is closed for the season, it’s also important to keep an eye on the water level.  Some years you will get an excessive amount of rain and snow. This will actually refill your pool and then some.  Your service company will likely provide winter check up visits. If you don’t want to mess with the water level in the winter yourself, we’d suggest you take them up on the winter checkups. 

Overfilling in winter can cause coping and tile to crack and loosen if ice builds up around them, damage to the deck, and more. You’ll want to pull back a section of the cover, drop a sump pump in and pump out some water to prevent this condition.

Why Doesn’t My Pool Overflow When It Rains

So what do you do when building a pool to prevent this?  Is there any way you can prevent your pool from overfilling?  Winter overfilling is often only preventable with pumping down the water, but if you have a built in overflow, that’s a great start.  Using a purpose made unit like the Overflow 3001 is one way to do it, but your pool builder likely has other options available as well

Make sure to ask your pool builder about this concern.  For some reason pool builders don’t include this inexpensive insurance on every pool they build.  It’s likely due to the fact that you need a place to drain the water to, and this can mean building a dry well or a drain pipe to daylight.

If your pool doesn’t have an overflow, there is an easier way to drain water out of your pool than using a sump pump.  There is most likely a hose bib between your pump and filter at your pool equipment. 

pool equipment next to a white house showing why doesn't my pool overflow when it rains as being resolved via a hose bib feature

If you attach a hose and run it to a storm drain or to the lawn, you can let your pool equipment drain down your pool for you.  Just make sure you set a timer so you don’t drain your pool down too far, and make sure you aren’t violating any local ordinances related to draining down your pool.

You might be thinking, I paid for an automatic water leveler, why do I have to worry about this?  Well, your automatic water leveler only adds water like a toilet valve, it doesn’t actually automatically level the water.  Most of the time we have to worry about evaporation with pools, not overfilling.  

Will My Pool Overflow From Rain?

There are parts of the country where a 3” rainstorm is common. Sometimes that’s enough water to fill your pool to overfilling.  When you know there is going to be a lot of rain, it’s not a bad idea to get setup to drain down the pool during or after the rainstorm.

What To Do If Pool Is Overflowing From Rain

1. Shut off the pool pump and any other equipment that is connected to the pool. 2. Remove any debris or leaves that have accumulated in the skimmer basket. 3. Check the pool filter and backwash the filter if necessary. 4. Lower the water level of the pool using a pool pump or a submersible pump. 5. Check the pool’s overflow pipe and ensure it is unblocked. 6. Disconnect any hoses that are connected to the pool. 7. Ensure the pool cover is securely fitted. 8. Monitor the pool water level and adjust as necessary.

Why Doesn’t My Pool Overflow When It Rains Summary

Now you understand, your pool is capable of overflowing. There are a few reasons why your pool doesn’t overflow when it rains. First, maybe your pool is equipped with an Overflow 3001. Second, perhaps the person who maintains your pool is using a sump pump or hose to mitigate the possibility. Lastly, you may be lucky enough to be in a climate that has an even balance of rainfall and evaporation. Either way, if you find that your pool is overflowing from rain, follow the 8 step process we described above.