Could also be worth checking your water pressure overall. Sometimes if the main pressure coming into your house is set too low, even a good valve struggles to keep things balanced. Quick way to test: grab a simple gauge from the hardware store, screw it onto an outdoor faucet, and see what you're getting. Should be around 40-60 psi. If it's lower, bumping it up a bit might smooth out those chilly surprises... just don't crank it too high or you'll have other issues to worry about, lol.
Actually, pressure might not be the main culprit here... I've seen houses with solid pressure still get that icy blast. Could just be your shower valve itself—some older or cheaper valves aren't great at balancing temps when there's a sudden drop. Had to swap mine out last year, problem solved.
Yeah, good point about the valve. But I'm curious—have you checked if your plumbing is set up with separate hot and cold lines running close together? Sometimes, especially in older homes, the cold water line feeding the toilet is tied in pretty close to the shower's cold line. When someone flushes, it suddenly draws cold water away, causing that quick temp spike. Upgrading to a pressure-balancing valve definitely helps, but sometimes rearranging or insulating pipes can make a noticeable difference too. Had a similar issue at my old place; swapping valves helped, but wrapping insulation around the pipes near the shower made it even better. Might be worth checking out how your plumbing lines are routed before investing in a new valve...
"Had a similar issue at my old place; swapping valves helped, but wrapping insulation around the pipes near the shower made it even better."
Insulation does help, especially in older setups. But I'm wondering—have you checked your home's overall water pressure? Sometimes, if your pressure's already borderline low, flushing can cause a noticeable drop in cold water availability at the shower. Had a client once whose issue improved significantly just by tweaking their home's pressure regulator...might be another angle worth exploring before rearranging pipes or valves.
Yeah, insulation definitely helped at my place too, but honestly, checking water pressure sounds like a smart move. I hadn't even thought about the regulator...might save some hassle before messing with pipes again. Good call.
