Managing your swimming pool during a rainy spring

Many areas of the country are experiencing heavier than usual precipitation, especially in the springtime.  With heavy rains come flooding, muddy water and debris in the pool.

How does rain affect pool water?

Rain is acidic and thus lowers the pH of your swimming pool water.  Acidic water can damage your pool’s heat pump and filtration system. Additionally, acidic water irritates the eyes and skin.  Rain also brings contaminants from the atmosphere and leaves and twigs from nearby trees.  This additional debris can incrementally affect your pool water’s pH, clog the filter and cause more problems if not addressed.

The most problematic part of heavy rainfall, however, is that algae has perfect breeding conditions:  acidic, nitrogen-rich water.  The best method for dealing with algae is a preventative method with algaecide — just a few preventative measures can go a long way!

Ways to manage your swimming pool during a rainy season:

  • Prevent an algae outbreak. Adding an algaecide to ward off an algal breakout after a rain is the best method.  However, if some algae has already started growing, you will need to add a small dose of a chlorine-alternative shock to kill off the already-growing algae.  
  • Brush the walls and floor. Regular brushing of the pool walls and floor can help remove any small algae particles so that they circulate into the filter.
  • Maintain proper circulation. Ensure the skimmer baskets and line basket are not clogged with debris and that the pump is working at normal rates. This will ensure the algaecide circulates around the pool to prevent algae from growing.  
  • Maintain proper filtration. A good filtration system can trap dead or circulating debris and algae.
  • Maintain proper disinfectant levels. Monitoring the pH of the water after a rainfall is very important as well as ensuring that you add the correct amount of algaecide or chlorine-alternative shock.
  • Lower water levels. If heavy rains are predicted, keep your pool water level low so that the rainfall doesn’t cause your pool to overflow.

If there’s a lot of rain:

When rain is heavy, pool equipment is at risk for flooding.  If flooding water threatens to submerge the pool pump, shut off power to the pool on the main panel and see if you can remove the pool pump safely and store it indoors.

If a pool pump is submerged and gets waterlogged, it will need to be replaced.  Please note that regular rainfall on pool equipment is fine; it is flooding and standing water that can be a real issue. An alternative solution is to put sandbags around your pool equipment to prevent flooding waters from come near the pool pump.

Depending on what surrounds your pool, water runoff might bring dirt, soil, mulch, debris, grass and other items into the pool. Use leaf rakes to remove the large debris and then a slow vacuum to get the rest, along with lots of brushing the sides and floor.  

Special phosphate removers (SeaKlear or Phos-free) will need to be used if soil and mulch are in the pool. Prevention is the best practice for this issue though.  Make sure your pool deck is sloped a quarter inch for every foot and that storm runoff drains are pointed away from the pool.  

In summary, prevention is the best way to making it through the rainy season with a clean and clear pool.

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Claire McDaniel

Claire is a swimming and nutrition expert who loves to educate and motivate others to healthier living. She swam competitively for 18 years, is a five time All-American, a Division I National Champion, was co-captain of Team USA at the 2007 World University Games and was named a finalist for the NCAA Woman of the Year Award. She also has a master’s degree in nutrition and is a Registered Dietitian Nutritionist. After swimming, Claire started coaching and has coached all over the US and even in Switzerland! Her experience and expertise about both swimming and health fuel her passion for Clear Comfort’s mission – to make swimming a 100 percent healthy activity for swimmers, coaches, lifeguards and pool staff.