Almost everyone has had to deal with hair clogging sinks, drains and septic system or sewer pipes at sometime in their life. It can be messy affair, take time and, in general, be a disgusting event to resolve. Why does hair cause so many septic tank problems when it goes down a drain?
The answer lies in what hair is made of. Hair is comprised of tough strings of proteins, somewhat similar to what fingernails are made up of. For a variety of complex reasons, these proteins are not as easily broken down by bacteria as organic waste is. They certainly are not even close to being broken down within the twenty four to forty eight hours they are held in the septic tank (the typical hold time in a septic tank for most septic systems).
As a result, hair survives pretty much intact for many months within the pipes, septic tank and drainfield of a septic system. Hair, in fact, can survive for hundreds of years if the environment is suitable. There are countless accounts of human remains being found in peat bogs that are hundreds of years old and the hair is still intact!
If a septic tank has a filter in the outlet baffle, hair will become trapped and is removed from the system during the periodic maintenance cleanings. If the septic tank has been sized correctly for the household and there is adequate hold time for the wastewater, the hair will settle and become part of the sludge layer at the bottom of the septic tank. It is pumped out with the rest of the sludge during the periodic septic tank pumping performed every two or three years. If there is no filter or the hold time is not adequate, the hair is free to flow throughout the system until it eventually reaches the drainfield (if it doesn’t cause a clog on its way there).
Clogs occur when hair encounters an obstruction and accumulates, forming a filter and trapping objects and organic waste flowing past. What starts as a couple of strands wedged in a pipe joint or trapped in a bend in the piping eventually will grow to a full blown clog over time. Slow flowing drains and backups are usually the consequence.
The best way to deal with these clogs is to try to mechanically dislodge them, using a snake or disassembling the piping to remove the clog. Many homeowners, however, will try to deal with these clogs by using chemicals to dissolve the hair. As had been cited many times in other blogs on this site, these chemicals are, in general, bad news. They may dissolve the clog but can also damage the bacterial environment in the septic tank, causing even more problems. Some of these chemicals may eventually make their way into the ground water table.
The best way to avoid septic tank problems attributed to hair is to prevent it from entering the system in the first place. Use screens and filters in sink and tub drains; humans constantly shed hair along with skin. Preventing some of this from getting into the system only reduces the chances you will have problems.