When a toilet is not flushing right, you might think the problem is low water pressure, but pressure has nothing to do with it. When a toilet doesn't work right, it's because it's not getting enough water. First check the tank. If the level seems low, adjust it by raising the float. Then check the water ports under the rim. They might be clogged with built-up mineral deposits. Using a small mirror, locate and clean each one, using a wire coat hanger dipped in white vinegar. With the proper water level and clean rim ports, chances are you'll be "flush" with success.