Backflow prevention and backflow testing can be a hidden world for many people, especially with the cryptic testing requirements. Let’s go over how backflow prevention works, what testing accomplishes and other important facts that all homeowners should know.
How Does a Backflow Preventer Work?
First, here are some basics: “Backflow” occurs when contaminated water flows back into a water system filled with potable – or drinkable – water, contaminating the whole system and causing major headaches. It’s important to prevent this whenever possible! This is typically accomplished with double-check valves or reduced pressure zones.
Here’s what the system does, broken down in three key stages:
1. Ordinary Operation of Water Systems
Water, especially water drawn from a public source, is under a lot of pressure from powerful pumps that enable the system. That high-pressure state allows water to flow into buildings very quickly, providing the necessary force that keeps showers working and prevents faucets from merely trickling. However, that pressure creates risks when something goes wrong.
2. An Unexpected Problem Comes Up
Let’s say that a problem occurs that rapidly reduces the high pressure of the interconnected water system. Maybe there’s a nearby fire and several fire hydrants are opened to put out the blaze, for example. Maybe an earthquake or construction problem breaks a nearby water main. Sometimes a catastrophic leak in a building, such as from frozen pipes, can also rapidly drain the system.
This creates a sudden demand for water due to the vacuum that’s created – a vacuum that systems aren’t designed to deal with. This leads to water being pulled from any connected plumbing system, including systems filled with dirty or contaminated water, which floods the drinkable water system. This water might include the following:
- Water from irrigation systems or soil: This water is unfiltered and often contains dangerous fertilizers and pesticides.
- Water from fire sprinkler systems: This water sits for years waiting to be used and collects toxic bacteria growths. It may also contain foam or antifreeze chemicals that are dangerous for humans.
- Water from sewage systems: It’s clear why no one wants this water in the system! Human waste harbors many dangerous bacteria and other contaminants.
3. The Backflow Prevention Valves Do Their Work
When a vacuum in the high-pressure system occurs, the backflow valves stop water from being pulled backward where it shouldn’t be. Assemblies can range from basic air gaps (the kind that keep water from backflowing into the sink) to complex reduced pressure zone devices (RPZDs) with dual check valves and a chamber with sensors to monitor current pressure. This is why owners sometimes see water coming out of top of backflow preventer, which is a sign that the preventer is maintaining a healthy pressure balance between two different systems, like backflow prevention valve on irrigation systems.
For the record, this isn’t just theoretical: Backflow into potable water systems has caused significant problems before, including poisoning schools and medical clinics. That’s why many local governments now require backflow prevention assemblies.
Where is Backflow Prevention Used?
Laws can vary from region to region, but backflow prevention valves are usually required on all public systems, groundwater wells and most water storage tanks with pressurized systems. This is also true in San Antonio, Texas, which requires backflow valves on irrigation systems, on-site sewage facilities and other various alternative water use systems. Chances are good you have a backflow assembly attached to your building, even if you weren’t aware of it before. If you are building a new water storage feature, like a well, you are also required to make sure a backflow prevention assembly is included as part of the setup.
Do I Need Backflow Prevention Testing?
Yes, you do! Backflow prevention systems don’t last forever and need to be properly tested and maintained so they don’t fail. Since even a single backflow incident can contaminate the entire water supply, it’s a major disaster that cities create laws to prevent – which leads to annual testing.
Backflow preventer testing in San Antonio is required each year. Residents will typically receive a notification letter about the test, or they will get a notification each quarter along with their water bill. However, people must take initiative in arranging the test themselves with a licensed backflow prevention assembly tester. Testers must be certified to test systems and provide documentation that the test was completed, as well as arranging for any repairs on worn down systems (another step required by law). If the assembly has additional features like firelines or recycled water, then the tester needs certification to test that particular type of system as well.
Fortunately, there’s an easy way to deal with all this: Contact Mr. Plumber and arrange your backflow test today. We’re certified to handle your testing needs, and our licensed plumbers are also ready to make any repairs or corrections to the assembly if something comes up. We can also answer any concerns you may have if the backflow preventer sprays water or other unexpected occurrences. Schedule now, and you won’t have to worry about it again!