My PC Was Soaked by Rainwater—Should I Replace the PSU and GPU?

The motherboard may also have been affected, even if it looks dry, because some sections can remain powered while the PC is plugged in. Once everything is completely dry, inspect for corrosion or residue and clean suitable components with 99% isopropyl alcohol. A damaged motherboard could potentially cause problems for other parts, so avoid powering the system until it has been inspected and cleaned.

Replace the power supply rather than trying to reuse it. Water may have reached the motherboard too, so remove and dry every component individually. Pat everything dry, use airflow, and give it several days in a warm—but not hot—dry location. Do not open the PSU because it can retain dangerous electrical charge. The GPU and other parts can be cleaned with high-percentage isopropyl alcohol if there is residue, then left to dry completely.

Patience is the safest approach here. Water mainly causes damage by creating shorts, so if nothing failed while it was wet, the parts might survive after thorough drying. Wait at least several days, and make absolutely sure there is no moisture trapped under components, connectors, or heatsinks before reconnecting power. I would test with a known-good replacement PSU rather than risking the original.