My wife and I just purchased our first house. I’m a young’en and know NOTHING about A LOT (especially plumbing). In the basement there is a tiled shower that has a 6″ drain cover. I was cleaning up the shower and pulled the drain cover off to clean it up. Under the cover I noticed that there was an additional hose end that was draining into the “hole” below the shower. In the “hole” (maybe 2″ in diameter) there was standing water. When I would pour water down the drain, the water would go in, but the level of water in the hole would remain the same.
My question is a two-parter. What could the hose in the drain be and why is there water that remains in the hole? I’m thinking that the water is some kind of barrier keeping the bad stuff out of the house, but like I said, I know nothing about house stuff. If this water is supposed to be there, how does it work and what keeps it from draining?
Any info you could provide regarding this mysterious drain is greatly appreciated! Thanks.
Replies
The shower drain, properly so, has a trap installed. It's a U-shaped section of pipe. All your fixtures have one. Showers and bathtubs have them in the floors, and toilets have them cast in to the base of the toilet itself. Sinks have them in the cabinets, where they are visible and therefore their operation apparent.
The purpose of the trap is to provide a seal to keep sewer gas from coming back into the house. The trap holds water up to the level of the pipe on the outlet side of the trap. Beyond the trap along with the drain is a vent line, which usually goes up through the roof. The vent lets air enter behind water flowing down the drain. If the vent were not there (or gets plugged by a rare animal) the water flowing down the drain would create a suction and draw the slug of water out of the trap and expose the house to sewer gas.
A trap is kept filled by the water that goes down the drain. A trap on a fixture that goes unused for months can dry up from evaporation. This can happen if, for example, you live alone and only use one of several sinks or bathrooms. You'll notice it from the smell. The solution is to pour some water down the drain every few months to keep it full.
A hose in the drain is a bit unusual. If it's smaller than say an inch, it could perhaps be a condensate drain for an air conditioner or furnace, or an overflow from a humidifier. If it's 1½" or larger, it could be a drain from a basement appliance, perhaps a washing machine. It's not the standard way of hooking one up, but probably fine.