| O-Ring |
 |
Round rubber washer used to create a watertight seal, chiefly around valve stems. |
| OEM |
|
Original Equipment Manufacturer |
| Oakum |
|
Loosely woven hemp rope that has been treated with oil or other waterproofing agent; it is used to caulk joints in a bell and spigot pipe and fittings. |
| NPSP (Discharge) |
|
Non Point Source Pollution. Nutrients, sediments, toxic substances, and pathogens that degrade waterways. NPS occurs mainly through storm water runoff. |
| Obscure Glass |
|
A glass that lets light through but is not totally transparent. |
Oil Powered |
|
A water heater that uses oil as its fuel source. |
| Offset |
|
A tubular component which permits the offsetting of a drainage run in the same basic direction. |
| One-Piece Toilet |
|
A toilet in which the tank and bowl are manufactured as a single vitreous china fixture. One-piece toilets usually have a lower profile than two-piece toilets. |
| Open Front |
|
A colorless, odorless fuel derived from the earth, consisting primarily of Methane (CH4). Odors are added to aid in leak detection. |
| Orbital Weld |
|
A circumferential, full fusion weld used to join together two lengths of tubing. It is a GTAW welding process. Usually to join coiled lengths. |
| Orifice |
|
An opening through which gas is discharged and whereby the flow of gas is limited and/or controlled. |
| Outlet / Discharge |
|
The opening through which the water exits the pump. |
| Outlet Sewer |
|
Pipe section in a septic system which runs between the septic tank and the drainage field. |
| Outside Diameter / OD |
|
The diameter of a pipe measured from the outside edge. |
| Overflow Hood |
|
On a bath drain, the decorative hood concealing the overflow. |
| Overflow Tube |
|
The vertical tube inside a toilet tank that directs water into the bowl in case the ballcock malfunctions. It is usually part of the flush valve. It prevents potential water damage caused by a tank overflow. A "constant-running" condition alerts the user to a problem. On most toilets, the overflow tube also has a refill tube flowing into it, which directs water from the ballcock through the overflow tube to the bowl, after a siphon break. |
