If you’ve got a toilet that just randomly runs, stops, then runs again throughout the day without you even touching the handle, this is for you. In this video I break down what’s actually happening inside the tank, why it’s a super common issue, and how to fix it fast without calling a plumber. Most of the time the culprit is the fill valve—there’s a little seal inside that wears out over time—so instead of messing around with tiny parts, I usually just replace the whole valve because it’s only about 7 to 10 bucks. I show you how the fill valve works (float up = water stops, float down = water fills), where the water comes in, and how it also refills the bowl through that small hose. Then I walk you through my quick method: shut off the water, flush the tank, slide the collar up, pull the top portion off, and swap the new valve head on without draining the tank completely. After that it’s just setting the height, aiming the nozzle toward the overflow tube, cutting the hose to size, and turning the water back on so the level sits about a half inch below the tube. Quick, easy, no tools required, and you’re done.