Backflow Prevention & Testing in Largo, FL
Keep contaminated water out of your drinking water. Contact Positively Plumbing for backflow preventer installation, testing, and repair from a licensed Pinellas County plumber.
Backflow Prevention for Largo Homes and Businesses
Your home’s potable water supply is meant to flow one direction — from the water main to your taps. Backflow is the undesirable reversal of that flow, where non-potable water is pushed or pulled back through a cross-connection into the clean water you drink. Backflow prevention devices are the physical barrier that stops it, protecting both your home’s potable water systems and the public water system everyone shares.
Positively Plumbing installs, tests, and repairs backflow preventers across Largo. Kevin runs the crew. We handle the assembly, the annual test, and any repair, then file the paperwork the water supplier requires — with a written price before the work starts and no hidden fees. Cross connections can lead to backflow and water contamination, and getting the right device installed and tested is how you prevent it.
How Backflow Happens: Backpressure and Back Siphonage
Backflow occurs through a cross connection in two ways, and understanding them explains why the device matters.
Back Siphonage
Back siphonage is caused by negative pressure in the water main — when a main break, heavy fire-hydrant draw, or other event drops supply pressure and water flow stops, the resulting suction can pull water backward, like drinking through a straw. Non-potable water from an irrigation line or other source gets siphoned into the potable water supply.
Back Pressure
Back pressure backflow is caused by downstream pressure that’s higher than the supply pressure — often from pumps, boilers, or a pressurized system pushing water backward against the normal flow. When the downstream pressure exceeds the water main’s supply pressure, water reverses through the cross connection.
Either way, the fix is a backflow preventer sized to the hazard, installed where the cross connection occurs.
Types of Backflow Preventers
Different situations call for different types of backflow preventers.
The right one depends on the hazard level and whether you need protection against back siphonage, back pressure, or both.
Air Gap
An air gap is a physical separation — a vertical gap between the water supply outlet and the rim of the receiving vessel — with no moving parts to fail. It must be at least twice the diameter of the supply pipe and never less than one inch high. An air gap is the most effective backflow prevention method and offers maximum protection, but it breaks the pressurized line, so it isn’t practical for most connections.
Reduced Pressure Zone Assembly (RPZ)
A reduced pressure zone assembly uses two independent spring-loaded check valves with a pressure differential relief valve between them, plus shutoff valves and test cocks. It protects against both back pressure and back siphonage, which makes it the device for high-hazard situations. High-hazard situations — medical facilities, boilers, chemical connections — often require a Reduced Pressure Zone assembly, and RPZ assemblies are mandatory for high-hazard applications.
Pressure Vacuum Breaker Assembly (PVB)
A pressure vacuum breaker assembly uses a spring-loaded check valve and an air inlet valve, with shutoff valves and test cocks. A pressure vacuum breaker assembly protects against back siphonage only — not back pressure — so it’s used where downstream pressure won’t exceed supply pressure. It’s common on residential irrigation systems.
Double Check Valve Assembly (DCV)
A double check valve assembly uses two spring-loaded check valves in series. A double check valve assembly is effective against low hazards and is commonly required for low-hazard, non-health cross connections where you need physical separation between a non-potable water system and the potable line.
Atmospheric Vacuum Breaker
Atmospheric vacuum breakers are suitable for low-hazard applications and are among the simpler, more affordable devices, though they have installation limits — no shutoff valve downstream and continuous-pressure restrictions.
Backflow Testing in Largo
Because these are mechanical devices with springs and seals, a check valve fails over time, so backflow assemblies must be tested periodically to confirm they still hold. Florida requires backflow protection in areas with irrigation systems and pools, and the Florida Building Code has mandated backflow preventers for residential irrigation systems since 1990. Testing is typically required every one to two years depending on the device type and your local utility, and the water supplier tracks compliance.
We run the test with calibrated gauges on the test cocks, check the first check valve and second, verify the relief valve on an RPZ, and confirm the assembly is holding to testing protocols. If it passes, we file the results with your water supplier. If it fails, we tell you what’s wrong and quote the repair. Keep your test and maintenance records — failing to maintain backflow prevention devices can create liability in a contamination incident, and utilities can disconnect service for non-compliance.
Our Backflow Services
Backflow Testing & Certification
Annual or biennial testing on your RPZ, PVB, or double check assembly, with results filed to your water supplier. We test to protocol and give you a straight pass/fail with any repair quoted in writing.
Backflow Preventer Installation
New installation sized to the hazard and the cross connection — irrigation, pool fill, boiler, or commercial connection — installed to plumbing codes with the proper shutoff valves and clearances.
Backflow Repair & Rebuild
When an assembly fails a test, we rebuild or replace the failed check valve, relief valve, or seals and retest to confirm it holds. Often a rebuild costs far less than a full replacement.
Cross-Connection Control
Assessment of where a cross-connection puts your potable water at risk, and the right device to provide maximum protection — physical separation between drinking water and any non potable water system.
Who Needs Backflow Prevention
Homes With Irrigation Systems
Required by Florida code since 1990; residential irrigation systems in Florida must have backflow preventers installed.
Homes With Pools
Florida requires backflow protection where pool fill lines connect to the potable supply.
Properties With Wells or Reclaimed Water
Any auxiliary, non-potable source connected near the potable system.
Commercial Buildings
Restaurants, medical facilities, and any business with boilers, chemical connections, or process water.
Fire Suppression Systems
Where additives or standing water could reverse into the supply.
Why Pinellas County Homeowners Choose Positively Plumbing
Right Device for the Hazard
We match the backflow preventer to the actual cross connection and hazard level — not the most expensive assembly on the shelf.
Testing, Filing, and Repair Under One Roof
We test, file with the water supplier, and repair or rebuild if it fails — one call handles the whole compliance cycle.
Upfront Pricing in Writing
The test, any repair, and installation cost are spelled out before we start. No hourly meter, no surprise add-ons on the invoice.
Family-Owned and Locally Operated
A Largo-based company that values community and personalized service. Kevin runs the trucks, so the plumber who installs your device is the same one who tests it next year.
Licensed and Insured Professionals
Fully licensed and insured, carrying general liability and workers’ compensation. Installed and tested to plumbing codes the first time.
Service Areas
We provide hydro jetting and drain cleaning plumbing services across Largo, Clearwater,
Pinellas Park, and communities throughout the greater Tampa Bay area.
Not sure if you’re in our service area? Call (727) 625-0603 — we’ll tell you straight.
What Customers Say About Us Online
Frequently Asked Questions
Get Your Backflow Testing or Installation Estimate
Need a backflow test, a new preventer, or a repair? Contact Positively Plumbing today for straight answers and a written estimate. We handle the test, the filing, and any repair — so you stay compliant, and your drinking water stays clean.