Plumbing glossary

Cleanout - a capped fitting that lets a plumber get a snake or camera into the drain line without pulling a fixture. If your house lacks one, expect to pay more for main-line service, because the plumber may have to remove a toilet for access. P-trap - the U-bend under a sink that holds a water seal against sewer gas. A dry trap is the most common cause of a sewer smell in a rarely used bathroom.

GPM (gallons per minute) - flow rate at a fixture. WaterSense labeled showerheads use no more than 2.0 gpm versus a 2.5 gpm standard; WaterSense bathroom faucets use no more than 1.5 gpm against a 2.2 gpm federal maximum. GPF (gallons per flush) - toilet flush volume. The federal standard is 1.6 gpf, WaterSense labeled models are 1.28 gpf or less, and pre-1994 toilets used up to 6 gpf.

Expansion tank - a small tank that absorbs thermal expansion in a closed system. Pressure regulator (PRV) - a valve that reduces incoming street pressure to a level your plumbing can live with. Backflow preventer - a device stopping water from flowing backward into the supply. Hose bib - an exterior spigot; the frost-free type has the shutoff set back inside the heated envelope.

Hydro jetting - high-pressure water cleaning of a drain line, as distinct from snaking, which bores a hole through a blockage. Trenchless - sewer repair methods that avoid full excavation. Sanitary sewer lateral - the pipe from your house to the municipal main; in most places it's the homeowner's responsibility for at least part of its length, and where that responsibility ends is a local question worth asking your utility.