
Your pool’s water is sanitized using a careful combination of chemicals, making it safe for you to swim in. However, since outdoor pools are exposed to the elements, even a little rainstorm may disturb the equilibrium and damage your pool.
Everyone may benefit from a little rain, but you should know what to do if your pool is heavily flooded. For example, pool water is cloudy after rain.
How Does Rain Affect Pool Water? In general, a little mist or drizzle is nothing to worry about, but heavy rains might result in the problems listed below that will need to be fixed.
It Lowers Your PH
The pH balance of the pool water must be neutral for safe swimming. Perfectly balanced pool water falls between 7.2 and 7.6 on the pH scale of 0 to 14. Anything below this point causes the water to become acidic, while anything over this point causes it to turn alkaline.
Between 5.0 and 5.5, rainwater’s pH level is mildly acidic. Rain gets considerably more acidic, leaning towards the 4.0 range, when it interacts with air pollution.
As a consequence, when rainwater reaches the pool, its acidity will change the water’s chemistry and lower the pH level.
What does rain water do to a pool? Numerous problems might arise from acidic pool water. In addition to swimmers’ itchy skin and inflamed eyes, metals will corrode and pool surfaces will get discoloured. You must add soda ash to increase the pH level in order to rebalance the water.
It Dilutes Your Water Chemistry
Large volumes of rainwater added to your pool can dilute the water, disturbing the alkalinity, a buffer that absorbs pH level changes and maintains the water’s stability. Pool water may even turn green after rain.
As rainwater contains no pool-related chemicals (things like calcium cyanuric acid and chlorine), it won’t raise any of those levels – which is a good thing! However, because of the diluted water, the pool will also need new chemical additions. This is why pool water turns green after rain.
It Raises Your Water Level
To maintain a pool clean, the water must be circulated. The pool draws water from the main drain and the skimmers filter it and then use wall jets to restore it to the pool. The water level in your pool must be kept at the midway point of your skimmer.
Two things will happen if it falls below that point:
- Only water from the main drain will be circulated
- The skimmers will take in air, which can seriously damage your filtration equipment
What causes the water to drop? Evaporation.
Can you fill a pool with rain water? It is very acidic so you can’t just let it rain to fill the pool.
It Can Cause Drainage Issues
Raising the water level is one thing, but too much rain can cause your pool to overflow. While your pool is equipped with drainage points, sometimes the rainfall is just too much, and the overflow can lead to flooding in your backyard.
It’s critical to have the appropriate pool drains in place to address this. You may add strip drains, spot drains, and French drains to let extra water flow away from the pool and securely off your property.
What To Do Before a Storm

Monitoring the weather might help you reduce the impact that rainfall will have on your pool.
Here are some suggestions to help you prepare for a storm:
- Don’t fill your pool with rain water. If you fill the pool with rain water it will be too acidic so don’t let the pool fill with rain water.
- Don’t drain the pool. Don’t be tempted to empty the pool in order to reduce flooding in the event of severe rainfall. The pool’s water is essential for supporting the construction and keeping it in place by adding weight. If the pool is drained, intense rains may flood your yard with groundwater, which might cause the pool to explode.
- Clean up the backyard. Take everything out of the pool area that can be damaged in a strong storm. Things like pool accessories or toys, patio furniture, and any other objects that could be blown into the pool are a hazard that need to be taken care of to keep from damaging the pool.
- Turn equipment off. Inclement weather can be unpredictable and devastating. During the storm, be careful to switch off your electrical equipment to prevent catastrophic damage.
- Test & balance the water. You’ll be in control and need to maintain the pool water less after the storm has passed if you test and balance the water beforehand. The water in the pool may avoid being unduly tainted during the rain by being added with chlorine and algaecide.
- Prep for extreme weather. Storms with a lot of rain may also cause damage to your pool’s exposed areas. If your pump is outdoors, disconnecting it and covering it with a tarp is also a smart safety precaution. If you have a regular pool cover or solar cover, we advise rolling it up on its reel and fastening it. The last thing you want to do is having to buy new equipment because of some rain.
What To Do After a Storm – Testing Pool Water After the Rain

To repair your pool after it has been damaged by significant rain, follow these instructions:·
- Pump water from your cover. If you happened to have a cover on your pool when the rain struck, you may have a pool of water sitting on the cover. The simplest way to do this is to use a pool cover pump before removing the cover.
- Check the water level. You’ll probably have too much water in the pool after significant rain. You may quickly pump off the extra water by backwashing with your pool filter. To do this, you must connect a hose to the filter and operate it on the “waste” or “backwash” mode. You’re back in business as soon as the water level drops to the skimmer’s midpoint.
- Turn on your system. Refill your skimmer basket, put the pump back in “filter” mode, and start the water pumping once again.
- Shock the pool. Refill your skimmer basket, put the pump back in “filter” mode, and start the water pumping once again.
- Test the water & add chemicals. Rebalance the pool water by using a testing kit to find out where the pH, alkalinity, calcium, and free chlorine levels are at, and top up the water with the necessary amounts to bring the pool water back to a neutral state.
Although rain is a natural cleaner, it may be problematic and even dangerous in a pool.
Light rain exposure shouldn’t be a big problem, but you should be aware of the safety measures and maintenance procedures required during periods of high rains to maintain your pool operating at its best.