What is a Backflow Preventer/Assembly?

A backflow assembly is an approved, testable assembly composed of two independently acting, approved check valves, including tightly closing resilient seated shutoff valves attached at each end of the assembly and fitted with properly located resilient seated test cocks.

Double Check Valve Backflow Assembly

Reduced Pressure Zone Backflow Assembly

Backflow preventers/assemblies prevent the entry of harmful substances into drinking water supply. Contaminants or polluting substances may enter the drinking water source when the pressure of polluted source exceeds the pressure of the potable source. This action is called backflow and it is typically caused by back siphonage or backpressure.

Owners must have the assembly tested by
a registered backflow-prevention assembly tester once a year.
An untested backflow assembly is considered a potential hazard.

The type of backflow assembly used is determined by the degree of hazard.

Hose Bibbs Vacuum Breaker

Use one for your garden hose!
When you connect your garden hose to a fertilizer or pesticide applicator you are creating a cross-connection therefore you will need a backflow preventer. If the pressure in the main water lines drops a vacuum is created that will pull the pesticide-laced water into your home contaminating the water.

Water pressure drops are not uncommon. It may happen when firefighters use a fire hydrant for firefighting or a field operations crew repairs a broken water main.

State Regulation

The State of Texas adopted regulations effective July1, 1995, stating that all testable backflow prevention assemblies shall be tested upon installation by a recognized backflow prevention assembly tester.

Backflow prevention assemblies that are installed at facilities considered to be high hazard as defined by state regulation must be tested annually by a recognized backflow assembly tester. [Water Distribution 290.44(h)(4)].

City of Arlington Requirements

In accordance with current ordinances, the Building Inspections and the Water Utilities Department regulate the installation and testing of backflow prevention assemblies. The water Resource Services (WRS) Section of the Arlington Water Utilities Division requires that all backflow tests are completed on a TCEQ approved test form (Word) (PDF) and a copy forwarded to the WRS office. WRS maintains a list of accredited testers who have received the required state accreditation.

Backflow Ordinance