The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

Plumbing Repairs And Utilities

Dangerous Connections

21. Definitions

a. DANGEROUS CONNECTIONS. A connection through which the potable-water supply can be contaminated.
b. AIR GAP. The unobstructed vertical distance from the lowest opening from any pipe or faucet
supplying water to a tank or plumbing fixture down to the flood-level rim of the receptacle.
c. SAFE AIR GAP. An air gap across which water cannot be siphoned to the water supply system.
d. FLOOD LEVEL. The horizontal plane (usually at the rim of a plumbing fixture) at which water overflows into channels not directly connected to any drainage systems when water is flowing into the fixture at maximum rate.

c. INDIRECT WASTE OR CONNECTION. A waste pipe which does not connect directly with the building drainage system but discharges into it through a properly trapped fixture or receptacle.

f. BACKFLOW PREVENTERS, SIPHON BREAKERS, AND VACUUM BREAKERS. Devices which prevent backflow into a water supply system through submerged or partially submerged supply outlets.

22. Protective Measures

The potable-water supply system must be protected from possible contamination caused by backflow of sewage, waste water, or other impure water. Rack-flow is often the result of negative pressure in parts of the piping system causing siphon action through a branch outlet which is submerged below the flood level of a fixture. If supply mains are located below fixtures, impure water may flow by gravity into supply lines unless adequate preventive devices are installed.