Backflow Prevention

What is Backflow?

As part of its obligation to supply safe drinking water, the City of Lampasas maintains a program to prevent backflow and cross-connections between potentially hazardous substances and the City water supply.

Backflow is the unwanted reversal of flow of water which might carry unclean water or other hazardous substances into the public water supply and private plumbing. Backflow can occur in a number of circumstances that might draw water from places such as garden fountains, swimming pools, or lawn sprinkler systems into City water supply lines. Backflow can also carry water into your plumbing if it is connected to any outside water source. One example would be a garden hose connected to an external faucet with the end left in a mud puddle in a garden area.

Backflow Causes

Two conditions cause backflow: back siphoning and back pressure. Back siphoning can occur if the pressure in a pipe system drops and causes a vacuum that pulls water from other areas of the system toward the vacuum.

Heavy usage elsewhere or a main break could cause water pressure to drop in main lines, causing back siphoning to occur which would pull water from your plumbing or irrigation system into the public supply and your home’s plumbing.

Backpressure generally occurs when a pump is introduced to apply pressure to a system of pipes, or water comes under the influence of gravity, such as raising the height of the water above the ground. Simply lifting the end of a hose filled with water would place the contents of the hose under back pressure.

Required Annual Tests

Annual tests of Backflow Prevention Assemblies are required--and must be completed by a registered Backflow Prevention Assembly Tester (BPAT).

Note: Backflow prevention assemblies on fire protection sprinkler systems are required by the State Fire Marshal to be tested and/or repaired by a BPAT, who is a full-time employee of a fire protection sprinkler company that is licensed with the State Fire Marshal's Office.

Backflow Prevention

The City requires devices called backflow prevention assemblies (BPAs) to be installed anywhere a connection that could allow tainted water into the City system or private plumbing exists. These devices are subject to testing by a qualified backflow prevention assembly tester upon installation. In many cases, they are subject to periodic tests later, as well.

Common locations where BPAs are required are swimming pool automatic refill lines, refill lines for garden ponds and decorative fountains, and landscape irrigation systems. We also require hose bibb vacuum breakers on all external faucets to prevent backflow from garden hoses.

Backflow devices must be considered “approved,” which means they meet specifications set by the University of Southern California Foundation for Cross Connection Control and Hydraulic Research. An important detail set out in these specifications is that the device must be in-line testable (Testable while installed with active water service). 

Plumbing Codes and State law dictate minimum standards for backflow prevention. Public water systems such as the City of Lampasas Water Department must meet or exceed the state standards and carry the responsibility for enforcing them.

The City is subject to fines or other sanctions from the Texas Commission on Environmental Quality (TCEQ), which regulates water and wastewater operations ion the state, if we fail to locally enforce backflow prevention rules. 

Determining Which Type of Backflow Preventer to Use

The type of BPA applied in a situation depends on the level of hazard and the type of backflow which could occur.

The Texas Commission on Environmental Quality (TCEQ) classifies water as either "health hazard" or "non-health hazard". Health hazard means the water contains organisms or chemicals that could seriously sicken people or even lead to death if consumed. Non-health Hazard means the water is not likely to cause serious illness, but would not be desirable to drink from the standpoint of taste or appearance.  

Types of Backflow Devices and their Applications

  • Reduced pressure zone backflow prevention assembly (RP): health hazard, non-health hazard, protects against back siphoning and backpressure
  • Double-check valve backflow prevention assembly (DCVA): non-health hazard, protects against back siphoning and back pressure
  • Pressure vacuum breaker (PVB): health hazard, non-health hazard, protects against back siphoning, but not back pressure
  • Spill-resistant vacuum breaker (SVB): health hazard, non-health hazard, protects against back siphoning, but not back pressure
  • Atmospheric vacuum breaker (AVB): health hazard, non-health hazard, protects against back siphoning, but not back pressure.
  • Air gap: health hazard, protects against back pressure and back siphoning.

Non-conforming Backflow Preventers

Backflow preventers not conforming to these rules for a given application and which are worn out or broken and require replacement, must be replaced by a backflow preventer which does comply with the rules for the given application

Backflow Device Testing

Backflow device testing must be submitted as part of the building final inspection, or as part of an Annual or Semi-Annual testing process.  All Backflow Tests must be submitted to https://www.vepollc.com/