Should You Run Your Pool Pump When It Rains?

Written by Michael Dean
December 19, 2023

pool pump in the rain

While it’s true that a bit of rain never hurt anyone, it is definitely not the best news for your pool. Rainwater contains all sorts of contaminants, and when it enters your swimming pool, your pool water’s pH and chlorine levels may get skewed. If this is the case, you might be wondering: should you leave your pool pump running while it’s raining?

In this article, I will answer the above question and go over other pressing questions regarding pools and rain. Let’s dive in.


Main Takeaways

  • Pool water can quickly become dirty due to the pollutants in rainwater, skewed pool chemistry, changes in levels of water chemistry, particles of dirt and debris, etc.
  • You can clean a dirty pool after the rain by running your filter, refilling fresh water, manually cleaning the pool yourself, clearing out the skimmer basket, etc.
  • Minimize the pool becoming dirty, green, or cloudy by using a pool cover and rainproofing your pool area, especially if you live in a wet region prone to heavy rainfall.

Should You Run Your Pool Pump When It Rains?

I recommend running the pump during and after rain for several reasons. First of all, rain introduces contaminants to your pool, as the droplets are capsules of debris, dirt, chemicals, pollutants, and more. By running the pump when it rains, you can keep up with an active cycle of eradicating these impurities through the pool’s filtration system.

Rainwater can also severely affect the chemical balance of your pool. Acid rain can upset the system’s delicate pH balance and dilute sanitizing agents. So, running the pump can help distribute and mix the water and chemicals uniformly to better maintain that balance.

That said, I do not always recommend running the pump while it’s raining. For instance, in a severe electrical storm or thunderstorm, you’re better off with a pool cover and a shock treatment afterward. I will cover this more in-depth below!

Benefits of Running a Pool Pump When It’s Raining

Running your pool pump during rain can offer a few advantages.

Debris Removal

Rainwater introduces a lot of debris into the swimming pool. Running the pump allows the filtration system to catch and remove these impurities on an ongoing basis, preventing them from settling to the bottom of the pool floor and affecting water quality. This makes for a much easier cleanup process once the rain clears up.

Chemical Balance

As I mentioned above, rainwater dilutes the chemical balance of your pool, including your chlorine and pH. Running the pump circulates the water constantly, which aids in maintaining the chemical balance. However, you should always test the water after the rain, just in case!

Enhanced Filtration

Continuously running your pump and filter system during a rain storm improves the clarity of the water, trapping and removing smaller contaminants carried into the water by the rain. This helps your pool fend off issues such as algae growth in your pool.

Preventing Staining

Rainwater introduces foreign minerals and metals to the pool, which would lead to staining if not filtered out properly. By running the pump, these foreign contaminants won’t settle into the pool’s surfaces and cause discoloration to your precious pool walls and floor.

Are There Times You Should Not Run Your Pump When It’s Raining?

As I mentioned, running your pump when it’s raining is not always a good idea. Here are the situations where it’s better to shut off your pump.

Electrical Storms

This is a big one. During heavy thunderstorms with lightning, it’s always safer to switch off all electrical equipment (including pool pumps) to prevent the possibility of electrical damage or hazards. Lightning strikes can be disastrous, causing power surges or damage to the pump or other electrical components. And equipment that is storm-damaged is pretty much unsalvageable!

Heavy Flooding

Interestingly, although pool pumps pump water and are designed to be waterproof, pumps are not designed to be completely submerged in water. So, if your pool pump is located in an area prone to flood during heavy rain, turn it off. Do not turn it back on until it is dry. If you live in an area prone to flooding, I recommend raising your pump to prevent it from being fully submerged.

Limited Filter Effectiveness

During exceptionally heavy downpours, running the pump may have no effect. Intense rain or turbid water that’s too heavily contaminated and coming in drones could overwhelm the pump’s system. In this case, it’s best to keep the pump turned off and just wait it out.

Do You Need to Run Your Pool Pump After It Rains?

Yes, of course! Running your pool pump while it’s raining is not an absolute must; running it after it rains is non-negotiable.

If the period of rain was light and brief, your pool should be fine, but I still recommend running the pool pump to help clear out the impurities. And if it was a heavy rainstorm, run the pump for at least 4 to 6 hours (one turnover rate) to allow the filter and pump to filter out any contaminants that would have entered the pool.

While running the pump after it rains is important, here are some other post-rain best practices:

  • Skim the water
  • Test and rebalance the pool chemicals
  • Shock the pool if necessary
  • Check the water level of the pool
  • Empty the skimmer basket
  • Check pool equipment to ensure everything is working properly

By following these steps, you can help keep your pool clean and healthy even after it rains!

What Does Rain Do to a Pool?

While pure rainwater shouldn’t have a major effect on your pool, the pollutants each droplet captures on the way down turn the rain acidic. Rainwater also collects organic contaminants, such as algae spores, bacteria, and viruses, that will infiltrate your pool. To put it simply, each droplet that enters your pool brings with it a small dose of impurities and foreign contaminants you don’t want in your pool.

On top of that, rain can also dilute existing levels of pool chemicals, messing with the levels of calcium, chlorine, alkalinity, cyanuric acid, and other chemicals used to treat pool water. The dilution makes it even easier for unwanted issues to rapidly develop in the pool – especially since the rainwater also introduces contaminants to the pool!

For this reason, following rain and in the right conditions where the water is warm or stagnant, you can expect the pool to become cloudy and/or green fairly quickly.

Other Tips to Maintain Your Pool During Rain

Here are some of my top tips to maintain your pool while it’s raining (besides running your pool pump). This way, there’ll be less to clean up after the rain passes.

Empty Your Skimmer Basket

While it’s raining, you should be even more religious about checking your skimmer basket and emptying it out. Skimmers can quickly get filled up with organic matter after rain, so don’t skip this step!

Monitor the Water Level

You should always monitor the water level of your pool while it rains, as your pool may overflow. If your pool is overflowing, lower the water levels by either using a sump pump or a pool vacuum. Alternatively, you can switch your filter to “waste” or “backwash” to drain some water as the pool slowly fills up. Keep in mind that the ideal water level is halfway up the skimmer opening!

Do Not Skim the Water If It’s Storming

I know the temptation to skim your pool is strong when debris keeps entering your pool during a thunderstorm, but don’t do it! Prioritize your own safety. The last thing you want to do is hold a big metal pole when it’s storming outside. Even if you don’t see any lightning, it’s better to be safe than sorry!

Do Not Cover the Pool

While covering the pool seems like a nice idea to prevent debris from falling into the pool, I recommend leaving your pool uncovered when it’s raining. Why? Unfortunately, when it’s raining and storming, your pool cover may be destroyed by the high winds or from sharp or heavy objects falling on it.

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Keep Pumping

You shouldn’t let a little rain stop you from running your pool pump. It’s important to run the pump for at least 8 hours a day, and stopping that due to a little drizzle is counterintuitive. While there are some instances in which you should turn off your pump (such as a thunderstorm), for the most part, you can keep your pump running. In fact, this will help to keep the water cleaner and better balanced, making your job easier after the rain stops!

Check out my research on what to do with your pool before and after it rains. Any other questions about pool care and maintenance? Drop me a message!

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