After heavy rain, check pH and alkalinity first.

Yes. Rain messes with your pool chemistry — it’s acidic and dilutes everything. Start with a test.

Test pH and total alkalinity before anything else. Rainwater is naturally acidic (pH around 5-6) and can drop your pool’s pH fast. Get pH back to 7.4-7.6. Then check alkalinity — it should be 80-120 ppm. If alkalinity is off, pH will keep bouncing.

After that, shock the pool. Heavy rain brings in airborne dirt, pollen, and can wash in runoff. A good shock treatment kills any unwanted stuff and stabilizes chlorine levels. Run the pump for at least 8 hours.

If you got a foot of rain, you might also need to drain some water to keep the skimmer working right.

Your pool will be swimmable by tomorrow afternoon if you do it now.