The bowl on one toilet will not empty when we flush. We held the flapper open and it still didn't flush completely. It is obvious that the water level has dropped in the tank b/c you can see the old line from a week ago. This is now happening on a 2nd toilet in the house. The water level in that tank is lower, also. We have recently had the PRV on our water meter replaced. Didn't know if that could be part of the problem. There is no bubbling when we flush, but when we dump a bucket of water into the bowl when we flush, it DOES completely empty. We tried to add more water in the tank, but the water is already at the top of the overflow pipe. We can't figure out how to get more water in the tank with this short overflow pipe. We've lived here for 3 years and this has just started happening.