The annual anniversary is approaching
Testing is required on a schedule regardless of whether anything appears wrong, because an untested assembly is not a known working one.
A compliance obligation with a real purpose
Backflow Testing in Lake Shastina, CA
- Certified testers, calibrated gauges
- Report filed on your behalf
- Repair and retest in one visit
- Reminders handled at our end
A backflow prevention assembly exists to stop water flowing the wrong way through a supply. Under normal conditions the pressure differential holds everything moving in one direction, but a main break, hydrant use or heavy demand can reverse that pressure, and whatever is downstream can be drawn back toward the public supply.
These are mechanical devices with springs, seats and check valves, and they wear. An assembly that has not been tested is not known to be working, which is exactly why annual testing by a certified tester is a requirement rather than a suggestion.
Testing, reporting and repair
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Testing establishes whether each check valve holds against the differential it is supposed to hold against, and whether any relief valve opens at the correct point. It is performed with a calibrated differential pressure gauge by a tester holding current certification.
The result is a pass or a fail with recorded readings, and where an assembly fails it needs repair and retest rather than a note in a file. Both happen in the same visit wherever the parts allow.
What the assemblies are and where they are required
A reduced pressure zone assembly is the highest level of protection commonly fitted. It has two independent check valves with a relief valve between them, and if either check fails the relief opens and dumps water to atmosphere rather than allowing any reverse flow. They are used where the consequence of backflow is most serious.
A double check valve assembly has two checks in series without the relief. It is used where the hazard is lower, typically where the substance downstream is a nuisance rather than a health risk.
Pressure vacuum breakers and atmospheric vacuum breakers protect against back siphonage, where reverse flow is caused by negative pressure rather than by downstream pressure exceeding supply pressure. Irrigation systems are the most common application.
Which type is required is determined by the hazard rather than by preference: irrigation systems, fire suppression systems, boilers with chemical treatment, commercial kitchens, medical and dental premises, car washes and any process connection all carry their own classification. Fitting a lower level of protection than the hazard requires is a compliance failure independent of whether the device tests correctly.
What testing involves and what makes it fail
The assembly is isolated, test cocks are connected to a calibrated differential gauge, and each component is exercised in sequence. The first check valve is tested for tightness against a specified differential, the second likewise, and on a reduced pressure assembly the relief valve opening point is measured against its required value.
Failures come from a small set of causes. Debris on a seat is the most common and the most easily corrected, since a single piece of grit prevents a check from seating fully. Worn or hardened rubber seats and discs are the next, and they are consumable items that are expected to need periodic replacement.
Weakened springs cause a check to open too readily or a relief valve to lift at the wrong pressure. Corrosion inside the body affects older assemblies particularly, and in the worst cases means the assembly is no longer repairable and needs replacing.
Freeze damage is worth mentioning separately because it is entirely preventable. An assembly on an irrigation supply that was not drained before winter frequently cracks, and the failure is usually structural rather than a seat or spring issue. Winterization is far cheaper than replacement.
Reporting, deadlines and what happens if you miss one
Test results are submitted to the water authority, and the submission is part of the service rather than something handed back for you to deal with. Requirements vary by jurisdiction in format and deadline, and getting the submission wrong is as much a compliance failure as not testing at all.
Missing a deadline has consequences that escalate. The usual sequence is a notice, then a follow up with a firmer deadline, then in some jurisdictions interruption of supply to the property. For a commercial premises that last step is a trading interruption, which is why the reminder is worth handling properly.
Reminders are tracked at our end for properties on the books, so testing is scheduled ahead of the deadline rather than after a notice arrives. That is particularly useful for portfolios where assemblies sit on multiple properties with different anniversary dates.
Where an assembly fails and needs a part that has to be ordered, the authority generally needs to be informed and a repair timeline provided. That communication is handled rather than left to the property owner, who is usually discovering the requirements for the first time.
Repair, replacement and installation
Most failures are repairable with a rebuild kit containing the seats, discs, springs and seals for that specific assembly. Those kits are carried for common models, so a failed test frequently becomes a repair and a passing retest within the same visit.
Replacement becomes necessary where the body itself is corroded or cracked, where an assembly is old enough that parts are no longer manufactured, or where freeze damage has compromised the casting. It also becomes necessary where the installed device is the wrong type for the hazard, which is discovered more often than people expect on assemblies fitted many years ago.
Installation location matters and is frequently wrong on older work. Assemblies have orientation requirements, minimum clearances for testing and repair, and in the case of reduced pressure assemblies a relief port that must discharge to a location where a substantial flow of water will do no harm. An assembly in a pit with no drainage, discharging into that pit, is not compliant regardless of how it tests.
New installations are carried out with all of that accounted for, including isolation valves either side, adequate access, correct orientation, appropriate drainage for any relief discharge and, where the supply is exposed, provision for winterization.
Who needs one, and how the requirement arises
The requirement usually arrives in one of three ways, and understanding which applies makes the obligation considerably clearer.
The first is a service connection condition. Water authorities classify connections by hazard, and any property whose use falls into a classified category carries a requirement from the point the connection is made. Irrigation, fire suppression, commercial food premises, medical and dental facilities, car washes and any industrial process connection are the usual categories.
The second is a change of use. A building that previously carried no requirement acquires one when what happens downstream changes: a unit converted to food service, an irrigation system installed at a residential property, or a boiler fitted with chemical treatment. The obligation follows the use rather than the building, and it is frequently unknown to whoever made the change.
The third is a survey or an inspection. Authorities periodically audit connections, and a property that has carried an unregistered assembly for years, or that should have one and does not, tends to discover it this way. Where a survey finds no assembly on a connection that requires one, installation is the remedy and the timeline is usually short.
In all three cases the practical first step is the same: establish what is installed, what hazard classification applies and whether the two match. That is a survey rather than a test, and it is worth doing before a notice makes it urgent.
Assembly types and typical applications
| Type | Protection level | Common applications |
|---|---|---|
| Reduced pressure zone assembly | Highest, with relief to atmosphere | Chemical treatment, process water, high hazard |
| Double check valve assembly | Moderate, two checks in series | Lower hazard connections, some fire systems |
| Pressure vacuum breaker | Back siphonage only | Irrigation systems under continuous pressure |
| Atmospheric vacuum breaker | Back siphonage, intermittent use only | Simple hose connections and fill points |
| Air gap | Absolute physical separation | Where a permanent gap is practical |
How the annual test is carried out
01
Confirm the assembly and the requirement
Type, size, serial number, location and the hazard classification it is fitted to protect against.
02
Isolate and connect
Supply isolated with notice given where an interruption affects occupants or a business, and the calibrated gauge connected.
03
Test each component in sequence
Both check valves for tightness and, on a reduced pressure assembly, the relief valve opening point.
04
Repair and retest where it fails
Rebuild kits carried for common assemblies, so a failure usually becomes a repair and a pass in the same visit.
05
File the report and diarise the next
Submission to the water authority handled, and the next anniversary tracked so it does not arrive as a notice.
When testing or attention is needed
Water discharging from the relief port
On a reduced pressure assembly this means a check valve is passing. The device is doing its job, and it needs attention promptly.
A notice from the water authority
Deadlines escalate, and in some jurisdictions the end of that sequence is interruption of supply to the property.
An irrigation assembly that was not winterized
Freeze damage is common and frequently structural rather than repairable. It should be tested before the system is recommissioned in spring.
A new connection or a change of use
Hazard classification follows use. A change in what happens downstream can change what level of protection is required.
Visible corrosion or leakage at the assembly
Body corrosion affects older assemblies and can reach the point where repair is no longer possible.
You have no idea whether you have one
Very common, particularly on properties bought with existing irrigation or fire systems. A survey establishes what is fitted and what is required.
Backflow questions
Testing Requirements and What Failure Means
A compliance topic that most property owners encounter for the first time when a notice arrives.
Because a backflow assembly is a mechanical device with springs, seats and moving checks, and those wear, foul with debris and weaken over time. Unlike most plumbing, there is no symptom when it stops working: water continues to flow normally in the correct direction and the only thing lost is the protection against reverse flow, which you find out about when the reverse flow event happens. Annual testing is the only way to know the device still does what it was installed to do.
Most failures are repairable, usually with a rebuild kit containing the seats, discs and springs for that assembly. Kits for common models are carried, so a failure frequently becomes a repair and a passing retest within the same visit. Where a part must be ordered or the body itself is corroded or cracked, you get a timeline and a quote, and the water authority is informed of the repair schedule rather than simply receiving a failed result with no context.
The property owner, in almost every jurisdiction. The authority sets the requirement, maintains the records and issues the notices, but arranging a certified tester and submitting the result is the owner's obligation. For tenanted commercial properties the allocation between landlord and tenant depends on the lease, and it is worth establishing that in advance rather than when a notice arrives addressed to whoever the authority has on file.
On a reduced pressure zone assembly, a discharge from the relief port means one of the check valves is no longer holding and the relief has opened to protect the supply. The device is doing exactly what it exists to do, and it needs attention promptly because it will continue discharging and because the protection is now operating on its last line. A small intermittent discharge during pressure fluctuations can be normal, but sustained flow is not.
The testing schedule follows the anniversary rather than the season, but the more important winter point is winterization. An assembly on an irrigation supply that is not drained before a freeze frequently cracks, and that damage is structural rather than a seat or spring issue, which usually means replacement rather than repair. Draining it in autumn costs very little and prevents the most common cause of assembly replacement.
No. Testing must be performed by a tester holding current certification, using a gauge with current calibration, and the report has to come from that certified tester for the authority to accept it. Both the certification and the gauge calibration have expiry dates, and a test performed with an out of calibration gauge is not valid even if the work was done correctly. It is entirely reasonable to ask to see both.
Also in the catalog
Related Water System Work
Backflow assemblies sit within a wider water system that benefits from the same attention.
Scheduled, tested, filed
Book the Annual Test Before the Notice Arrives
Testing by a certified tester with a calibrated gauge, repairs carried out in the same visit wherever parts allow, and the report submitted for you.
Anniversaries are tracked at our end, which matters most for portfolios with assemblies on several properties.