Water from your fertilized lawn shouldn’t be flowing back into your home through the kitchen or bathroom taps. That’s why residential irrigation systems in Texas must be connected to a suitable backflow prevention assembly (BPA).

In Austin, the Austin Water Utility administers a backflow prevention program in combination with state and local codes to ensure that BPAs are installed, maintained, and tested wherever backflow may be a risk.

What’s Backflow?

Backflow is the reverse flow of non-potable (not suitable for drinking) water or other substances back into the piping of the consumer’s drinking water system or the public water system. It can occur in two ways: back-siphonage and backpressure.

Back-siphonage occurs when there’s a loss of pressure in the public water system. A line break or open fire hydrant will reduce the pressure in the municipal lines, drawing water back into your home from your irrigation pipes, and even into the public water supply.

Backpressure occurs when a source of pressure is greater than the pressure from the public water supply. Greater pressure can be caused by a pump installed on the irrigation system, pool, or landscape pond, which are all sources of non-potable water. This non-potable water is then pumped into the potable water supply for your home and the public system.

What’s a cross-connection?

A cross connection is any potential or actual physical connection between drinking water lines and any source or system containing non-potable water or other substances. An irrigation system is a cross connection containing the following hazards to a drinking water supply:

• Chemicals injected into the irrigation system (e.g. fertilizers)
• Animal waste, pesticides, herbicides, and fertilizers entering through the sprinkler heads
• Parasites, pathogens, and insect larvae living in the system’s water
• Connection to other water sources, such as rainwater harvesting systems and private wells

BPA Regulations

All public water systems are required by the Texas Commission on Environmental Quality (TCEQ) to protect their drinking water distribution systems with a Cross Connection Control Program. The regulations are laid out in the Texas Administrative Code Title 30, Chapter 290, Subchapter D, Rules and Regulations for Public Water Suppliers. Regulations on backflow prevention and cross-connections are set out in 30 TAC 344.50-344.52.

Austin Water manages its Cross Connection Control/Water Protection Program in conjunction with city ordinances in Chapter 15-1, TCEQ rules, and the most recent Uniform Plumbing Code adopted by the city. BPAs must be a design approved and listed by the University of Southern California Foundation for Cross Connection Control and Hydraulic Research. There’s also a list of approved BPA manufacturers and types on the Austin Water site.

Testing Regulations

BPAs have internal seals, springs, and moving parts that are subject to clogging, wear, fatigue, or freeze damage. For these reasons all devices have to be tested on a regular basis to make sure they’re functioning properly.

The TCEQ requires testing by a licensed BPA tester upon installation, repair, replacement, or relocation of a device. BPAs used in irrigation systems designated as health hazards are tested annually (30 TAC 344.50 (e)). Testing requirements are covered as well in (30 TAC 290.44 (h)(4)).

In the Austin Water Utility distribution area BPAs must be tested each year to industry standards by backflow prevention assembly testers (BPATs) licensed by the (TCEQ) and registered with Austin Water Utility. The BPAs are tested for operational effectiveness using methods approved by the TCEQ and printed in the University of Southern California’s Cross Connection Manual (USC-CCM). Each BPAT must use equipment that has been calibrated by an approved gauge testing company, and is within acceptable tolerances as set out in USC-CCM.

Customers with BPAs registered with Austin Water Utility’s Special Services Division (SSD) are sent reminder notices for testing every year. They must arrange and pay for the BPA testing, as well for any repairs, overhauls, or replacements of devices that fail the test.

Customers who have never registered their devices may not receive a notice. However, they are still responsible for complying with testing, maintenance, and reporting requirements.

Failure to meet these requirements is a violation of Chapter 15-1 of the Austin City Code, which could result in criminal or civil penalties, with fines for each day of non-compliance and suspension of water service.

Testing and Maintenance Reports

BPATs must submit a complete and legible Test and Maintenance Report (TMR) to the Austin Water Utility for each BPA tested. The report includes such information as:

• Specific assembly location on the property
• Reason the assembly is installed. Must be a specific hazard from the official hazards list of the SSD
• Whether the BPA is installed according to manufacturer’s recommendations and local codes
• Description of BPA repairs (if applicable)
• Retesting of BPA after repairs (if applicable)
• Gauge readings
• Date gauge used for the test was last tested for accuracy

Sometimes parts need to be ordered before the BPAT can make repairs. In this case the BPAT indicates when he expects to do the repairs, and sends in the TMR. Another TMR is filled out when the repairs are done.

If a BPA fails the test, and is replaced, the tester lets the SSD know if it was discarded or stored until repaired. After repairs, another test is done and a TMR filled out.

The original TMR must be submitted by the tester within five calendar days of the test. It can either be entered online in the WEIRS (Water Environmental Integrated Recordkeeping System) database, or a hard copy can be mailed to the SSD. The BPAT keeps a copy for himself, and gives one to the customer.

Types of BPAs

BPAs protect against two types of hazards — pollutants and contaminants. Pollutants are non-health hazards that affect the taste, color or odor of water. Contaminants are health hazards that cause illness, disease, or death.

Here are some common BPAs providing different levels of hazard protection:

Double Check Valve Assembly (DCVA):

• Can be installed above ground or in a pit or vault
• Consists of two independently acting, spring-loaded check valves
• Effective against backpressure and back-siphonage
• Isolates only non-health hazards
• Testable

Reduced Principle Backflow Assembly (RPBA)

• Also known as a reduced pressure zone assembly (RPZ)
• Consists of two independently acting spring-loaded check valves with a hydraulically operating, mechanically independent, spring-loaded pressure differential relief valve in between
• Effective against backpressure and back-siphonage
• Isolates health and non-health hazards
• Testable

Pressure Vacuum Breaker Assembly (PVB)

• Consists of an independently acting, spring-loaded check valve, and an independently acting spring-loaded air inlet valve
• Effective against back-siphonage only
• Isolates health and non-health hazards
• Testable

Air Gap

• Consists of a vertical, physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel
• Separation must be at least twice the diameter of the water supply pipe, but never less than one inch
• Effective against backpressure and back-siphonage
• Isolates health and non-health hazards
• Not testable

South Austin Irrigation are the experts in irrigation system troubleshooting and repair.  Call us at (512) 534-7449 or contact us online to keep your sprinkler system operating at peak performance.