If you have an irrigation system in Texas, you must have a backflow prevention assembly (BPA) installed and tested annually. These assemblies prevent any backflow of contaminated water through cross connections into the drinking water supply.
Backflows and Cross Connections
Backflow is the reverse flow of non-potable (not drinkable) water or other substances back into the supply lines of the consumer’s drinking water system or the public water system. It can occur due to backpressure or back-siphonage.
Backpressure happens when a source of pressure from a non-potable system is greater than the pressure from the public water supply. A pump installed on the irrigation system or pool can create a high-pressure source, causing non-potable water to flow into the drinking water supply for the home and public system.
Back-siphonage happens when the public water system loses pressure. Water main breaks, open fire hydrants, and high water demand reduce pressure in the municipal pipes. Non-potable water can then be drawn back from an irrigation system into the home and public supply.
A cross connection is a physical connection between potable (drinkable) water and used or untreated water, industrial fluid, gas, or any substance that could make the water unsafe to drink.
Common home cross connections:
- Garden hose: back-siphonage can occur if a garden hose is turned on and attached to an insecticide sprayer or submerged in a swimming pool or bucket of soapy water.
- Private well: Backpressure can happen where a pump supplies untreated water from a private well that is connected to the drinkable water supply.
- Irrigation system: back-siphonage and backpressure can occur from an irrigation system that may contain the following hazards:
- Private well or rainwater harvesting system providing an auxiliary water supply for irrigation
- Chemicals and/or fertilizers pumped or injected into the irrigation system
- Animal waste, herbicides, pesticides, and fertilizers drawn into the water supply plumbing through the sprinkler heads or drip emitters
- Pathogens, parasites, and insect larvae living in the system’s pipes
BPA Regulations
The Texas Commission on Environmental Quality (TCEQ) requires all public water systems to establish a Cross Connection Control Program, as set out in the Texas Administrative Code.
Following TCEQ regulations, Austin Water manages its Cross Connection Control/Water Protection Program in conjunction with city ordinances. BPAs must be installed according to the most recent Uniform Plumbing Code adopted by the City, and they must be an approved design listed by the University of Southern California Foundation for Cross Connection Control and Hydraulic Research. There’s also a list of approved BPA models and manufacturers on the Austin Water site.
Why Test Irrigation BPAs?
Irrigation BPAs have moving parts, internal seals, and springs that become worn, clogged, fatigued, or damaged during hard freezes. They need to be tested on a regular basis to ensure they’re working properly. It may not be obvious that a BPA has failed or needs repair. However, if the water in your home tastes, looks, or smells bad, have the BPA checked immediately.
Testing Regulations
Testing by a licensed BPA tester is required by the TCEQ upon installation, repair, replacement, or relocation of an assembly. BPAs used in irrigation systems designated as health hazards must be tested annually.
BPAs in the Austin Water Utility distribution area are required to be tested annually by backflow prevention assembly testers (BPATs) licensed by the TCEQ and registered with the Utility. Each device is tested for operational effectiveness using methods printed in the University of Southern California’s Cross Connection Manual (USC-CCM) and approved by the TCEQ.
Reminder testing notices are sent out annually to customers who have BPAs registered with the Austin Water Utility’s Special Services Division (SSD). The customer must set up the appointment and pay for the testing, as well as for any resulting repairs, overhauls, replacements, and retesting of assemblies due to initial test failures.
Customers without registered BPAs might not receive notices, but they are still responsible for the testing, maintenance and reporting requirements. Failure to do so is a violation of the Austin City Code. Violations could result in criminal or civil penalties, with fines for each day of non-compliance, and possible suspension of water service.
Testing and Maintenance Reports
Each BPAT must submit a Test and Maintenance Report to the Austin Water Utility for each BPA tested within five calendar days of the test. The tester can either enter the report online in the WEIRS (Water Environmental Integrated Recordkeeping System) database or mail a hard copy to the SSD. A copy also goes to the customer, and the BPAT keeps one for himself.
BPA Types
Backflow risks are divided into two types of hazards: pollutants and contaminants. A pollutant is a non-health hazard — a non-toxic substance that is a nuisance, and affects the taste, color, or odor of water. A health hazard is a toxic substance, or contaminant, that causes illness, disease, or death.
The selection of a backflow prevention assembly depends on which risk is present. Here are some typical BPAs and their hazard protection levels, as well as the “air gap” prevention method.
Reduced Principle Backflow Assembly (RPBA)
- Also known as a reduced pressure zone assembly (RPZ)
- Includes two independently acting, spring-loaded check valves with a hydraulically operating, mechanically independent, spring-loaded pressure differential relief valve in between
- Protects against backpressure and back-siphonage
- Isolates health and non-health hazards
- Required to be testable
Pressure Vacuum Breaker Assembly (PVB)
- Consists of an independently acting, spring-loaded check valve, and an independently acting, spring-loaded, air inlet valve
- Protects against back-siphonage only
- Isolates health and non-health hazards
- Required to be testable
Double Check Valve Assembly (DCVA)
- Can be installed above ground, or in a vault or pit
- Consists of two independently acting, spring-loaded check valves
- Protects against backpressure and back-siphonage
- Isolates only non-health hazards
- Required to be testable
Air Gap
- Consists of an unobstructed, vertical distance between the end of a water supply outlet and the flood-level rim of the receiving receptacle
- Separation must be at least twice the diameter of the water supply pipe, but never less than one inch
- Protects against backpressure and back-siphonage
- Isolates health and non-health hazards
- Not testable
Call the licensed irrigators at Smart Earth Sprinklers at 512-694-1147 or contact us online for your sprinkler system inspection, repair, and maintenance needs.
