Backflow


Plumbing Code

Backflow

Pressure created by any means in the water distribution system, which by being in excess of the pressure in the water supply mains, causes a potential backflow condition.

Backpressure, Low Head

A pressure less than or equal to 4.33 psi (29.88 kPa) or the pressure exerted by a 10-foot (3048 mm) column of water.

Backsiphonage

The backflow of potentially contaminated water into the potable water system as a result of the pressure in the potable water system falling below atmospheric pressure of the plumbing fixtures, pools, tanks or vats connected to the potable water system distribution piping.

Drainage Backflow

A reversal in the drainage system.

Water Supply System Backflow

The flow of water or other liquids, mixtures or substances into the distribution pipes of a potable water supply from any source except the intended source.

(International Plumbing Code® 202.0)