When your plumbing sounds like a foghorn, it can be startling and confusing. The best thing to do when this happens is to determine where the sound is actually coming from. In most cases, you can fix the problem yourself, while in other more complicated instances you will need to call in a professional.
Toilet: In most cases, a foghorn sound coming from the plumbing often comes from the toilet. This particular sound coming from your toilet is due to an issue with the ballcock valve, more commonly known as the flapper. When the ballcock becomes old, damaged, or offset – it makes a very loud sound, similar to that of a foghorn. If you find that this is the source of the alarming noise, you will need to replace the valve.
Faucet: The foghorn noise can also be heard from any faucet in your home. Fortunately, this isn’t a major issue. If the faucet in your kitchen, laundry room, or even bathroom is beginning to sound loud and make a loud sound, then chances are there is a loose washer on the faucet. Due to constant use, screws and fixtures come loose. To resolve this problem, you can tighten the screws or replace the washer. If the sound continues or gets even louder, call a plumber.
Inside the Walls: Sometimes it is difficult to discover where exactly the foghorn sound is coming from and it can oftentimes be coming from behind your walls. If this seems to be the case, make sure you call a plumber before you begin sledgehammering your walls. There are multiple explanations as to why your plumbing is making a lot of unusual and loud noises; your pipes could be old, the brackets could have become loose or even the pipes have become loose.