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Backflow Basics
What is backflow?
Backflow is the unwanted reversal of water flow in a plumbing system. Instead of water flowing from the public supply into your property, contaminated water can flow backwards into the clean water supply. This can happen due to back-pressure (when your system's pressure exceeds the supply pressure) or back-siphonage (when negative pressure in the supply line pulls water backwards).
What is a backflow preventer?
A backflow preventer is a mechanical device installed on water lines that allows water to flow in only one direction. It contains check valves and/or air gaps that prevent contaminated water from reversing course and entering the public water supply. Think of it as a one-way valve that protects drinking water from contamination.
Why is backflow prevention important?
Backflow prevention protects public health by keeping contaminated water out of the drinking water supply. Without proper backflow prevention, fertilizers, pesticides, chemicals, sewage, and other hazardous materials could contaminate the water that you and your neighbors drink, cook with, and bathe in. Backflow incidents have caused serious illness outbreaks throughout history.
What can contaminate water through backflow?
Common contaminants include:
- Fertilizers, herbicides, and pesticides from irrigation systems
- Pool and spa chemicals
- Boiler treatment chemicals
- Fire suppression system additives
- Medical and dental equipment waste
- Industrial chemicals and solvents
- Sewage from cross-connections
- Stagnant water harboring bacteria
How do I know if I have a backflow preventer?
You likely have a backflow preventer if your property has:
- An irrigation or sprinkler system
- A fire sprinkler system
- A swimming pool or hot tub with an automatic fill
- A boiler system
- Medical or dental facilities
- Any commercial food service
- A well in addition to city water
Backflow preventers are usually located near your water meter, at the point where your irrigation system connects, or in a mechanical room. If you've received a notice from your water provider, you definitely have one that needs testing.
Testing Requirements
Is backflow testing required by law in Colorado?
Yes. Colorado state regulations and most local water authorities require annual testing of all backflow prevention assemblies. This is mandated by the Colorado Department of Public Health and Environment (CDPHE) under the Colorado Primary Drinking Water Regulations.
How often do I need to get my backflow preventer tested?
Most jurisdictions require annual testing—once every 12 months. Some high-hazard facilities may require more frequent testing. Your water authority will send you annual reminders with your testing deadline.
What happens if I don't get my device tested?
Failure to comply with testing requirements can result in:
- Warning notices from your water provider
- Fines ranging from $50 to several hundred dollars
- Water service disconnection
- Liability if a backflow incident occurs
Most water authorities send multiple reminders before taking action, but it's best to test on time to avoid any issues.
Who can perform backflow testing?
Only certified backflow prevention assembly testers can legally test devices in Colorado. Testers must hold a valid certification from an approved training program and maintain their certification through continuing education. Our technicians hold current Colorado certifications and are registered with local water authorities.
Who do I submit my test results to?
Test results must be submitted to your local water authority—the entity that provides your water service. This could be Denver Water, Aurora Water, Westminster, Arvada, Lakewood, or another local provider. We file test reports directly with your water authority on your behalf.
The Testing Process
What happens during a backflow test?
A certified tester will:
- Locate and visually inspect your backflow preventer
- Shut off downstream water and open test cocks
- Connect calibrated test equipment to the device
- Run water through the device while measuring pressure differentials
- Verify each check valve and relief valve is working properly
- Record all readings and compare to pass/fail criteria
- Complete the test report and file with your water authority
How long does a backflow test take?
A standard test takes 15-30 minutes per device, depending on the device type and location. RPZ devices take slightly longer than double check valves. If repairs are needed, additional time will be required.
Do I need to be home for the test?
Not necessarily. If your backflow preventer is accessible from the outside (most irrigation and fire system devices are), we can complete the test without you present. We'll coordinate access details when you schedule. If the device is inside or behind a locked gate, we'll need to arrange access.
Will my water be shut off during testing?
The water to the protected area (like your irrigation system) will be temporarily shut off during testing—usually for 15-30 minutes. Your main household water supply is typically not affected unless the device protects the entire property.
What equipment do testers use?
Certified testers use differential pressure test kits that measure the pressure drop across check valves and relief valves. These test kits must be calibrated annually and certified to ensure accurate readings. We use only calibrated, certified equipment.
Device Types
What types of backflow preventers are there?
The main types include:
- Reduced Pressure Zone (RPZ/RP) — Highest level of protection. Required for high-hazard connections. Has two check valves and a relief valve that opens if either check fails.
- Double Check Valve Assembly (DCVA/DC) — Two independent check valves. Used for low-to-moderate hazard connections like residential irrigation.
- Pressure Vacuum Breaker (PVB) — Uses an air inlet that opens when pressure drops. Common for irrigation systems. Must be installed above the highest point of use.
- Spill-Resistant Vacuum Breaker (SVB) — Similar to PVB but designed to minimize water spillage. Also must be installed above the highest point of use.
- Atmospheric Vacuum Breaker (AVB) — Simplest type. Non-testable. Used for low-hazard connections where continuous pressure isn't maintained.
What's the difference between RPZ and DCVA?
The key difference is the level of protection:
RPZ (Reduced Pressure Zone): Provides the highest level of protection and is required for high-hazard connections. It has two check valves plus a relief valve in between that will dump water if either check fails. This makes it "fail-safe" but can discharge water during a failure. Required for: commercial irrigation with chemical injection, fire systems with chemical additives, medical/dental facilities, boiler connections, and any high-hazard application.
DCVA (Double Check Valve Assembly): Provides good protection for low-to-moderate hazard connections. It has two check valves but no relief valve. More compact and won't discharge water. Common for: residential irrigation (without chemical injection), pools, and low-hazard commercial applications.
Which type do I need?
Your water authority determines the required device type based on the hazard level of your connection. Generally:
- Residential irrigation — Usually DCVA or PVB
- Commercial irrigation — Often RPZ, especially with fertigation
- Fire sprinklers — DCVA for standard systems, RPZ if chemical additives used
- Swimming pools — Usually DCVA
- Medical/dental — RPZ required
- Boilers — RPZ required
When in doubt, check with your water authority or ask us—we can help determine the right device for your situation.
How long do backflow preventers last?
With proper maintenance, a quality backflow preventer can last 15-25 years. However, internal components (rubber seals, springs, check valve seats) typically need replacement every 5-10 years. Factors affecting lifespan include water quality, usage patterns, and exposure to elements. Regular testing helps identify wear before it causes failure.
Can I install a backflow preventer myself?
Installation typically requires a licensed plumber and must meet local codes. The device must be installed at the correct height, orientation, and location, with proper clearances for testing and maintenance. After installation, it must be tested by a certified tester and registered with your water authority. We recommend professional installation to ensure compliance.
Common Problems
What causes a backflow preventer to fail its test?
Common causes of failure include:
- Worn rubber seals and o-rings (most common)
- Debris lodged in check valves
- Mineral buildup from hard water
- Corrosion of internal components
- Damaged springs
- Physical damage from freezing
- Age-related wear
Most failures can be repaired on-site by replacing worn components.
What happens if my device fails the test?
If a device fails, the tester will diagnose the problem. Many issues can be repaired on the spot—we carry common repair parts. After repair, the device is retested to confirm it now passes. If a device cannot be repaired, it will need to be replaced. You'll receive documentation of the repair and passing retest.
Why is water coming out of my RPZ?
RPZ devices have a relief valve that is designed to discharge water if the check valves fail or if there's a backflow condition. Some discharge during testing is normal. However, continuous discharge indicates a problem—either the first check valve is leaking, there's debris in the relief valve, or there's an actual backflow condition. This should be inspected promptly.
My backflow preventer is making noise. Is that normal?
Some noise is normal, especially when water is first turned on. However, loud humming, chattering, or vibrating sounds may indicate:
- High water pressure
- Worn components
- Debris in the valves
- Water hammer in the system
If the noise is persistent or unusual, have it inspected during your next test.
Can backflow preventers freeze?
Yes, and freeze damage is a leading cause of backflow preventer failure in Colorado. Water trapped in the device can freeze, expand, and crack the body or damage internal components. To prevent freeze damage:
- Insulate outdoor devices with approved covers
- Drain irrigation system backflow preventers before winter
- Have irrigation systems professionally winterized (blown out)
- Consider installing in a heated enclosure for year-round use
Colorado Regulations
What regulations govern backflow prevention in Colorado?
Backflow prevention is regulated at multiple levels:
- Federal: Safe Drinking Water Act sets minimum standards
- State: Colorado Primary Drinking Water Regulations (5 CCR 1003-1) require water systems to have cross-connection control programs
- Local: Individual water authorities (Denver Water, Aurora Water, etc.) implement and enforce specific requirements
Local requirements often exceed state minimums, so always check with your specific water provider.
What are the testing deadlines in Denver?
Denver Water requires testing annually, within 12 months of the previous test. They send reminder notices approximately 60 days before your deadline. If you're a new property owner, you're responsible for any existing testing deadlines—check with Denver Water to confirm your due date.
Do new constructions need backflow preventers?
Yes. New construction with irrigation, fire sprinklers, or other required connections must include appropriate backflow preventers. This is typically addressed during the permitting and inspection process. The devices must be tested before the system is approved for use.
I'm selling my property. Do I need to test before closing?
While not always legally required for the sale, many title companies, lenders, and buyers request current backflow test documentation. Having up-to-date test reports can smooth the transaction. If you're buying a property, verify the testing status and request current documentation.
Property-Specific Questions
Do residential properties need backflow testing?
Yes, if you have a backflow preventer installed—which you likely do if you have an irrigation system, pool with automatic fill, or fire sprinklers. Even simple residential sprinkler systems require annual testing of the backflow device.
I have a home irrigation system. What do I need to know?
If you have a sprinkler system, you have a backflow preventer that needs:
- Annual testing and certification
- Winterization (blowout) each fall to prevent freeze damage
- Spring startup inspection
Your device is probably a DCVA or PVB located near your water meter or where the irrigation line branches off. Our affiliate Denver Sprinkler Blowout offers professional winterization services.
I manage commercial property. What are my responsibilities?
Commercial property managers are responsible for:
- Maintaining all backflow prevention devices
- Ensuring annual testing is completed on time
- Keeping records of all tests and repairs
- Responding to water authority notices
- Ensuring tenant activities don't create new cross-connections
We can help commercial clients manage multiple devices and provide testing records for your files.
Do HOAs need to test backflow preventers?
If the HOA maintains common irrigation systems, fire sprinklers, or other systems with backflow preventers, the HOA is typically responsible for testing. Individual homeowners are usually responsible for devices serving their own lots (like residential irrigation), unless the HOA's CC&Rs state otherwise.
About Our Service
When will Denver Backflow Testing be available?
We're currently preparing to launch our backflow testing services. Check back soon for updates! In the meantime, our affiliated companies 5280 Sprinklers and Denver Sprinkler Blowout are available to help with your irrigation needs.
What areas will you serve?
We will serve the entire Denver metro area and Front Range, including Denver, Aurora, Lakewood, Arvada, Westminster, Thornton, Broomfield, Boulder, Littleton, Centennial, and surrounding communities.
Who are your affiliated companies?
Denver Backflow Testing is part of a family of irrigation service providers with over 15 years of experience:
- 5280 Sprinklers — Full-service sprinkler installation, repair, and maintenance
- Denver Sprinkler Blowout — Professional winterization services to protect your irrigation system
What services will you offer?
When we launch, we'll offer:
- Annual backflow testing and certification
- Repairs and rebuilds of all device types
- New device installation
- Test report filing with all Front Range water authorities
- Annual reminder service
- Emergency and same-day testing when available
Still have questions?
This FAQ covers the most common questions, but every situation is unique. When our service launches, we'll be happy to answer your specific questions. In the meantime, your water authority can provide information specific to your area.
Need Irrigation Services Now?
While we prepare to launch backflow testing, our affiliates are ready to help with your irrigation needs.