Hello. We have four toilets, 3 tubs - Our toilets have begun bubbling just about the time that one or more of the tubs are draining. What could our problem be?

Some where down line from your commode the line is stopped up. If all three of them bubble that means that the main line is stopped and the stoppage is probably out in the yard where the house line runs to the city sewer if you are connected, or if you are on a septic system it could be the line running to the septic tank or the tank itself might be full and need to be pumped out.