The reversal of flow from that normally intended. Hydraulic conditions that cause backflow include back siphonage, back pressure and aspiration.

Backflow Preventer

A device or an assembly used to prevent contamination of the potable water supply through an actual or potential cross-connection.

Backflow Preventer: Reduced Pressure Principle Backflow Prevention Assembly” or “RPZ”

A plumbing appurtenance consisting of two internally force loaded, independently acting check valves, designed to operate normally in the closed position, separated by an intermediate zone that includes an internally force loaded, hydraulically operated relief for venting to atmosphere, designed to operate normally in the open position, two tight-closing resilient shut-off valves, and four test cocks.


The joining of two pieces of pipe, or pipes and fittings, valves or other appurtenances.

Cross-Connection Control Device

A plumbing appurtenance installed in a potable water line to prevent any substance of any kind from being mixed.

Cross-Connection Control Device Inspector: CCCDI

An individual who holds an Illinois Plumbing License and who has been certified in accordance with 35 Ill. Adm. Code 653.802 (Specific Conditions and Installation Procedures) of the Illinois Environmental Protection Agency’s rules titled Design, Operation and Maintenance Criteria to inspect, test, maintain and repair cross-connection control devices and assemblies. The certification attests to an inspector’s understanding of the principles of backflow and back siphonage, and the public health hazard presented by the improper installation of cross-connection control devices.


Any pipe that carries waste water in a building drainage system. (See Appendix B.Illustration L.)

Drainage System

All piping within public or private premises that conveys sewage, rain or other liquid wastes to a point of disposal, but does not include the mains of a public sewer system or a private or public sewage treatment or disposal plant. The drainage system does not include the venting system. Drainage and venting are separate systems, although both are part of the overall plumbing system.

Grade or Pitch

The fall, pitch or slope of a line of pipe in reference to a horizontal plane. In drainage, it is usually expressed as the fraction of an inch fall per foot length of pipe. This may also be expressed as a percentage. (See Appendix B. Illustration O.)


The juncture of two pipes, a pipe and a fitting, or two fittings.

Non Potable Water

Water that is not of drinking water quality, but may still be used for other purposes such as irrigation

Potable Water

Also known or referred to as drinking water, is water that is safe to drink. It comes from surface and ground sources and is treated to levels that meet state and federal standards for consumption. Water from natural sources is treated for microorganisms , bacteria, toxic chemicals, viruses and fecal matter.

P.S.I. or psi

Pounds per square inch gauge of pressure.


A type of lawn faucet. A faucet used on the outside of a building to which a garden hose may be attached.

Sprinkler System

Lawn sprinkler system − a system of piping installed for irrigation purposes.

Sump Pump

A pump for the removal of storm, subsoil and clear water waste drainage from a sump.

Sprinkler Systems

Expertly built sprinkler systems designed to keep your lawn and landscaping looking their best day and night.

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Outdoor Lighting

Beauty and security combined by our experts to make your home as stunning at night as during the day.

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Drainage Solutions

Protect your property from unwanted water damage with our attractive and effective drainage systems.

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