The rain didn't ruin your pool.

Probably not. Heavy rain dilutes your pool chemicals and drops pH and alkalinity, but it’s fixable.

Don’t drain unless the water level is above the skimmer opening — even then, only pump down a couple inches. The real fix is testing. Grab your kit and check pH and alkalinity first. Rainwater is acidic, so you’ll likely need to raise both with pH increaser and baking soda (or alkalinity increaser). Then add enough chlorine to bump the free chlorine back up to normal levels — rain brings in organic crud that the chlorine needs to eat.

Wait until the water is clear and levels are balanced before shocking. Shocking with low alkalinity or pH can cause more problems.

Your pool will bounce back faster than your lawn.