Backflow Installation and Testing

Backflow can introduce contaminated water into the clean supply line of your house. It can also carry disease-causing bacteria like Shigella and E. coli.

Backflow Installation and Testing

Local laws require that apartments, condos, and commercial buildings install backflow preventer valves to isolate back-flow and preserve the sanitary drinking water system. These devices must be tested annually. Visit for more information.

Backflow is a dangerous phenomenon that occurs when your clean water supply reverses direction, bringing potentially contaminated water into your home. It can occur anywhere there’s a cross-connection between your potable and non-potable water supplies—like in your kitchen or laundry room. This reversal of flow is typically caused by a drop in pressure that allows higher-pressure dirty water to be “sucked” into your clean water lines (similar to how a straw works). Backflow is a serious health concern because the contaminated water could be used for cooking, drinking or cleaning—anything where it might come into contact with open wounds or mucous membranes. It can also corrode plumbing pipes and cause leaks.

The only way to prevent backflow is to have a properly installed and tested backflow prevention device. This is why it’s important to hire a licensed backflow testing company to service your residential or commercial backflow system. Backflow testing involves moving clean water through the backflow assembly in a reverse direction to determine whether untreated or contaminated water is being back-siphoned into your fresh, clean supply. It’s an annual process that ensures your family, customers and employees are protected from contamination and illness.

Most backflow devices are required to be tested by your local backflow inspector every year. Backflow preventers are installed at all points of a cross-connection—any point where your clean, potable water connects with a system that could introduce contaminants. Backflow preventers are usually located near appliances like toilets, hose bibbs, water heaters and dishwashers. This is because those appliances are the most common points of a backflow event.

There are different types of backflow preventers, depending on your needs and where your building is located. Some are more complex than others, but all have the same function: to protect your water supply by preventing backflow. Some have check valves, which are automatic valves that allow water to flow in one direction. Others have a reduced pressure zone valve, which has a second check valve with an internal sensor that measures pressure. If the sensors detect a sudden increase in pressure, it will open the primary valve and expel any water into drainage.

Types of backflow preventers

Backflow preventers are required to help ensure that contaminants don’t backflow into a potable water supply. These devices can help reduce the chances of a variety of different diseases and contamination issues that could affect people. Some of the most common concerns include fecal contamination, heavy metals and chemical waste. Diseases such as dysentery, typhoid and salmonella are all commonly spread through backflow events, while chemicals like insecticides and herbicides can be dangerous if they infiltrate the water supply.

Luckily, backflow preventers are designed to keep these kinds of contaminants out of the water supply by making sure that a system’s fluid flow is always in one direction. They also work to block off any kind of cross-connections to ensure that the water supply is kept clean for all of its users.

There are a few different types of backflow preventers to choose from when choosing a device for your home or building. The type of backflow preventer you need depends on the level of risk that is associated with your property and its plumbing system.

Reduced pressure backflow preventer backflow valves (RPZ) are the most reliable and effective type of backflow prevention device. They are used in the cross-connections that link a water system with hazardous chemicals, industrial fluids and fertilizers to prevent contamination.

They are often found in homes and commercial buildings with sprinkler irrigation systems or outdoor pools. These devices are usually located in the water line that connects to the irrigation and pool equipment, and they are often tested on a yearly basis to confirm that they are working as well as they should be.

Another type of backflow preventer is a double check valve assembly, which is typically used in lower risk properties. These devices are more cost-effective than RPZs and offer protection against both back siphonage and back pressure. However, they don’t protect against chemmigation, which is why RPZs are used in higher risk applications.

In high health hazard facilities, Seattle Public Utilities requires a Premises Isolation backflow prevention assembly to be installed downstream of the water meter/city union. These assemblies allow you to isolate your facility’s process plumbing from the drinking water system, ensuring that any contaminants cannot backflow from your building into the city’s supply.


Backflow prevention devices are designed to stop dirty water from entering your clean, drinking water supply. However, they can only do their job if they’re properly installed and maintained. A backflow preventer is a useful tool in residential structures and commercial or industrial buildings, but it can only function effectively if it’s placed where it can be accessed easily.

Back flow events are dangerous because they can contaminate your water with foreign materials, including bacteria and other contaminants. These devices are installed in plumbing systems at points where backflow could occur, which are called cross-connections. These are places where potable water connects to non-potable lines, such as a washing machine drain line that connects to a sink or dishwasher supply line. Other examples of cross-connections include fire sprinkler systems, mortuaries, chemical plants and lawn irrigation systems.

When installing these devices, it is important to install them where they are easy to access for maintenance and testing. This is especially true if the device is located in an area that’s considered a confined space, because this can cause unsafe conditions for backflow service technicians.

A confined space is an area in which entry and exit are restricted, which can cause dangers such as lack of oxygen or accumulation of dangerous gases. Installing backflow preventers in these areas requires the use of specific entry and exit protocols by trained backflow service technicians to ensure safety.

Another aspect of installing backflow preventers is ensuring that they’re properly sized for your system. This means determining the volume requirements of each water service and comparing it to the head loss specifications of your backflow assembly. If the head loss of your backflow device is too high for your system, it will not be able to handle the water flow and will not work as intended.

It is also crucial to ensure that the backflow preventer has a sufficient floor elevation, as this will allow water to flow freely. In addition, it’s essential that you have adequate clearance around the device to access its test cocks and shutoff valves.


As a homeowner, you can protect your home by having backflow prevention devices installed. However, these devices must be tested on a regular basis to ensure that they are working properly. Failing to test your backflow device can result in fines and even the loss of water service. Fortunately, our professional backflow testers can help you keep your water safe and up to code.

The purpose of a backflow test is to determine whether contaminated water is entering clean drinking water lines. This typically occurs when there is a cross-connection between the clean and dirty water lines, which can be caused by a sudden increase in water pressure. It’s important to have a backflow preventer installed at these points, which will stop the reverse flow of dirt and pollutants into your clean drinking water.

A backflow test is performed by a certified backflow tester who uses a special kit and gauges to check the BPD in your plumbing system to see if it is functioning correctly. The tester will connect the backflow testing kit to your backflow prevention device, then monitor the pressure in the gauges to check for any changes. If any backflow is detected, the tester will shut off your water main for about 30 minutes.

There are two general types of backflow prevention devices: air gaps and check valves. Our backflow specialists at Argent can install either one or both, as well as guide you through a complete assessment of your needs to find the best device for your property.

We have a team of highly trained and experienced backflow technicians who can inspect, install, repair and test your backflow device. We can also provide the documentation you need to submit to your local water provider, as required by municipal codes. Our backflow services are available to both residential and commercial clients, and we offer competitive rates.

Luz Martin