How many times have we heard such a statement when testing or repairing containment backflow prevention assemblies on critical services?

Through the years of enforcing San Antonio Water System’s Backflow Prevention Program and today actually being involved in the testing and repairing of assemblies, we have always had to deal with many critical services not having manifold installations (bypass arrangements). With manifold installations, one backflow prevention assembly can be turned off at a time for testing and/or repair. If the installation does not have a manifold backflow prevention assembly, the water has to be turned off to the facility. The only exception is if there is an additional belted water service or source to the facility.

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Ignorance by City Management on viable Cross Connection Control measures, along with the Arrogance of eliminating and/or basically Ignoring the detailed procedures established in all standards, codes and guidelines for viable backflow prevention programs, in my opinion, is negligent and fundamentally wrong. Where is common sense and moral responsibility in protecting the public water supply? Management (Cities) should be providing support for the Cross Connection Control Program instead of looking for reasons not to enforce it, in some instances.

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How do you know your drinking water is safe? If you have a sprinkler system at your house, officials at the Department of Health and Environmental Control (DHEC) say you could be as risk for cross contamination if you are missing a crucial part called a backflow preventer.

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Backflow Prevention Assembly Testers that are not adequately trained can rake havoc on all those associated with enforcement of backflow prevention measures, including the facility having the assembly to be tested and the backflow prevention assembly tester. Testers have to be trained to recognize cross connections, backflow situations and hydraulic situations affecting assemblies, correct assemblies for various hazards, resolution factors for malfunctioning assemblies, testing situations and nightmares situations and nightmares that affect testers and enforcement agencies, tester responsibilities, correct installations, etc. This is just to name a few.

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Commentary

Lawn Irrigation Systems – High Hazard or Low Hazard Cross Connection?

The following is a review of irrigation systems, their operation and considerations in the classification in the determination of high hazard (Health Hazard) cross connection or low hazard (Non-Health Hazard) cross connection. Over the years, Texas, along with a few other states have struggled some with irrigation Backflow Preventer requirements.

One of the first things the average person must understand is the fact that water pressure goes from a higher pressure to a lower pressure. Water pressure is not always constant and there are many variables that create these backflow situations. These situations can be very minute such as a pressure fluctuation caused by demand or the complete loss of water pressure due to water main breaks, fires in the area, high demand, piping design, etc. Additionally, pumps and elevations can create back-pressure situations.

There have been many cross-connection contamination events involving backflow situations. For every one documented it is estimated that 20,000 – 30,000 go undetected due to dilution. In documenting incidents in San Antonio for many years, we never documented an incident involving a residential lawn irrigation system. We did however, have an industrial site back-pressure almost a million gallons of contaminated water from an irrigation auxiliary water source into the city supply. The connection between the city supplied irrigation system and the auxiliary source was created without the water system’s knowledge. A Water Quality complaint involving illnesses led to the discovery of this incident. Also, we have been told about residential backflow situations involving standard lawn irrigation systems where the potable water was contaminated.

Wonder why we never officially documented an incident on any other irrigation systems? Let’s review how irrigation systems operate. There is a master valve and independent zone controllers. These valves only withstand .5 psi back-pressure. With the loss of water pressure – if the backflow preventer is not working as designed, the water in the irrigation system will be drained back into the potable water system. The irrigation system “does not have to be on for the system to be drained into the drinking water supply”. In San Antonio, a licensed irrigator and backflow tester actually set up an irrigation system display to demonstrate this at various irrigation conferences.

Backflow Prevention Assemblies – Studies have shown through annual testing of backflow prevention assemblies a failure rate(fouled checks) of 10-20%. If a backflow preventer is not

1.tested for approximately 10 years the failure rate is in the area of 85%. What does this mean? Loss of water pressure – failed backflow preventer – and you are drinking water from your irrigation system! It’s Diluted!

In Houston, as an example, there was no requirement to test their irrigation Pressure Vacuum Breaker backflow protection assemblies installed on residential irrigation systems when Hurricane Harvey hit. Many had been installed for over 25 years without testing, and the majority would not prevent backflow and operate as designed.

Hurricane Harvey – Houston floods- many of these backflow preventers were under several feet of contaminated water. Water pressure lost – these failed backflow prevention assemblies would allow the flood waters to be drained right through the pressure vacuum breakers into the public drinking water system.

Most States classify all irrigation systems a “high hazard cross connection” as detailed in plumbing codes, AWWA, ASSE, etc. Currently in Texas – the Texas Commission on Environmental Quality (TCEQ) has classified the simple residential irrigation systems as a “low hazard”. This determination comes from what irrigation systems were 60 years ago when the systems weren’t thoroughly understood. Additionally, there was no chemical injection, drip irrigation involving toxic root killer, aux. water sources, etc., as we are seeing in today’s world.

TCEQ regulations apply to annual testing of high hazard (health hazard) cross connection Backflow Preventers only, with no annual testing requirement on low hazard cross connection assemblies. Some cities are not requiring annual testing on the simple irrigation systems and are citing the plumbing codes and TCEQ regulations as reasoning for not requiring monitoring, to assure assemblies are actually tested annually.

Issue – If the irrigation systems were moved to a high hazard classification, the impact would be on home owners having irrigation systems and water purveyors that will be required to track the periodic testing. This would present a cost to both water purveyors and home owners. However, many cities have realized the hazard and are requiring annual testing. There are some requiring periodic testing of simple lawn irrigation systems, e.g., at a minimum tested every 2-3 years.

The public – We have yet to explain to the average citizen how their irrigation operates and all the hazards we see today, that they understand and demand their city enforce the backflow protection as detailed in plumbing codes and national organizations as mentioned above.

 

2.Back to the original question – High hazard or low hazard? Test annually – or periodic – or just forget about the irrigation backflow protection all together? Shouldn’t it be, that if you want water for a special use, you should be required to protect the potable water supply? Or maybe we just rely upon the dilution factor? Is the solution to Cross Connection Control in general – Dilution? NO!

Ask This Question – Why Test Backflow Prevention Assemblies?

1. Ensure assembly is still installed.

2. Ensure Backflow Protection hasn’t been by-passed.

3. Ensure hazard hasn’t changed with chemical injection, aux. water sources, etc.

4. Ensure the checks have not been removed.

5. Ensure checks haven’t been knocked out due to water hammer

6. Ensure assembly working as designed

7. Testing and Maintenance required in all plumbing codes.

Irrigation Study Request: What could be considered, is a detailed study on lawn irrigation systems like was done on fire lines with the effect of stagnant water on the public drinking water systems. This detailed the results of pressure fluctuations and loss of water pressure, thereby, draining stagnant water into the potable water system. If such a study were to be conducted on lawn irrigation systems that indicated irrigation systems are not a hazard – then we need to stop requiring testable backflow protection on the simple irrigation systems and go back to the duel checks from 70 years ago or just require no backflow protection. This is basically what we have now if the backflow protection is not tested and maintained. Nothing!!!

Numerous Cities and States Struggle with Lawn Irrigation Backflow Preventer Requirements, which includes periodic testing! What’s Wrong with Our Water Industry That This Issue Has Not Been Addressed Through Public Education? What’s Your Thoughts on Irrigation systems and Protecting Your Drinking Water?

Commentary by Fred Baird – He has been in the backflow industry for over 50 years and was involved initially in the development and enforcement of San Antonio Water System’s backflow prevention program for 30 years. Additionally, he served on the AWWA M-14 Cross Connection Control Manual – 3rd Ed. –Ad-hoc committee, which re-classified all lawn irrigation systems as a high hazard (health hazard) cross connection.

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As most know in the backflow world there are approximately 50 different test procedures for Backflow Prevention Assemblies (BFPAs). They all vary somewhat and all basically evaluate, to some degree, if a BFPA is operating as it’s designed to.

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