If your toilet starts to overflow, the first thing you should do is turn off the water at the source. This will help to prevent further damage and minimize the mess. Once the water is turned off, you can begin to assess the situation and decide how best to proceed. If the toilet is simply clogged, you may be able to fix it yourself by using a plunger or a toilet auger. However, if the toilet is overflowing due to a faulty flush valve or another more serious issue, it’s best to call an expert for assistance. In either case, taking quick action can help to prevent extensive water damage and make the problem easier to solve.