After the installation process, the reduced pressure zone device installed on plumbing systems requires regular tests by certified plumbers. Illinois water protection codes state that RPZ valves must be tested at least once every year. These tests are essential as they ensure that the valves are operating efficiently to protect the city water supply and drinking water from contaminants.

Because of their design, RPZ backflow preventers experience more high volume and pressure loss than double-check systems. Plumbers must account for these losses when designing drainage systems. Fluctuations of pressure, either downstream or upstream, will prompt the RPZ assembly to discharge small amounts of water periodically.

RPZ backflow preventers must be set up in areas with adequate drainage because a large volume of water will flow from the relief valve. For this reason, RPZ assemblies shouldn’t be installed in areas where the discharge water can cause damage — adequate drainage must be considered in areas fitted with RPZ valves.

Debris in your device can be removed by cleaning its seal. Over time, dirt and grime can build up, reducing the effectiveness of the device’s seal. To eliminate debris from your preventer, remove the spring assembly and thoroughly rinse it until the debris is gone.

For a municipal water system, if at any time the pressure at homes exceeds the pressure on the supply side, the two RPZ valves close preventing backflow. If either of the check valves leaks, the relief valve is designed to open and discharge water to the outside, ensuring that water never returns to the supply line.

RPZ valves are pivotal in preventing toxic chemicals, hard metals, pesticides, and other harmful compounds from contaminating water supplies. In residential buildings, a RPZ device is used with sprinkler irrigation systems, boiler systems, fire suppression systems, and forced-air furnaces where it acts as a safety mechanism.

The three-valve RPZ and the five-valve RPZ are the common RPZ testers approved for testing backflow systems. Since the five-valve RPZ tester allows testing procedures to take place without disconnecting any hoses, it is the most popular tester.

Air gaps and air gap devices are essential if you wish to avoid your dishwasher flooding with contaminated water. Plumbing codes in many states require air gaps to be included upon dishwasher installation, so air gaps may be essential in keeping your house up to code. States that do not require an air gap typically require a "high loop" drain connection that uses gravity to prevent backflow.

High pressure in a backflow prevention device can trigger a pressure relief valve. When opened, the valve will leak until the pressure returns to normal levels. High pressure indicates a problem in your water system, not your backflow preventer.

In 1933, Chicago hosted the World’s Fair and, unintentionally, a backflow disaster. The sewage and plumbing systems in Chicago at the time were undersized, and the influx of visitors led to disease caused by a contaminated water supply. Around 100 deaths and over 1000 cases of amoebic dysentery later, people realized that backflow was not something that should be taken lightly. Since 1933, plumbing codes have been created that require backflow prevention devices to be installed in water applications. Today’s plumbing codes essentially eliminate the risk of backflow, but proper understanding of how backflow prevention systems work is key to understanding if the systems are protecting your home and business. In this article, you can find information on what backflow is, types of backflow prevention devices, how these devices work, and how to install them in your home.

A backflow prevention device is a product that ensures water can only flow in one direction. There are multiple types of backflow prevention devices, and they all work best in specific applications. All backflow preventers, no matter the type, protect clean water lines from wastewater contaminants. The following are three common types of backflow preventers:

You can install some backflow prevention devices yourself, and others must be installed by a licensed plumber. The ease of installation depends on the type of device and where it will be installed.

In a typical RPZ assembly, two one-way valves are connected to prevent water from returning to the supply line. This system works by ensuring that the incoming fluid has a higher pressure than the water entering the downstream supply. To prevent minor backflow leakage, the closure of one valve creates a pressure differential, thus tightening the valves and effectively sealing the system from backflow.

Back siphonage is caused by negative pressure in the supply system. An unexpected pressure decrease within a system can cause water from the sewer line to be pulled back into the clean water line. Back siphonage most commonly results from a breakage or repairs on a water main or from heavy demand such as firefighting.

Also, use of pesticides or fertilizers in your backyard together with your home’s fire suppression system poses a danger. The standing water in your water supply system can get trapped and lead to bacterial and mineral growth, which can contaminate your clean water supplies.

Backflow is a plumbing term that refers to the pollution of a clean water line by contaminated water flowing in the reverse direction. Backflow occurs in cross-connections, such as in dishwashers and reverse osmosis systems, between potable and non-potable water lines and results in water that is unsafe to consume. For example, dirty dish water can siphon into your clean water line and dirty your drinking water. Two types of changes in water pressure, back pressure and back siphonage, are the primary causes of backflow.

Dual inlet air gap devices can connect two dishwashers to one drain line or drain both a dishwasher and a water filtration system simultaneously. These devices are particularly useful if you have an under-sink reverse osmosis system and want to avoid contaminating other appliances.

RPZ calibration tests should be done annually by accredited contractors and plumbers. While most companies only undertake calibration tests on the gauge on an RPZ tester, it is a good idea to test the system for leaks, inspect wear and tear of the valves, and account for pressure differences if any. Testing the entire RPZ assembly allows early detection of malfunction within the parts of the RPZ unit.

Backflow testing is required for businesses on a yearly basis. Some states, such as Texas and California, require homes to be tested annually for backflow as well. Even if your local legislation does not require backflow testing, it is recommended that you get a licensed plumber to check on your home's plumbing. To test for backflow, plumbers shut off your water and use gate and relief valves to check for leaks, unwanted movement, and the functionality of backflow preventers. If backflow testing is not required by law where you live, you can test for it yourself. However, backflow testing tools are expensive and testing can be difficult, so it is recommended that a professional checks your system for potential harm.

Atmospheric vacuum breakers (AVB) prevent backflow in hose, faucet, and spigot applications. AVBs contain a check valve that opens an air vent when the system loses pressure. When open, the air vent breaks the vacuum, and the water supply line is sealed off. This process prevents back siphonage from occurring when pressure is lost in the supply line.

Check valves come in many types, and installation will vary based on what you buy. The Watts LF7RU2-2, for example, can be installed both horizontally and vertically. Many valves can be installed yourself, and more complex units will likely require the help of a plumber. You should check the documentation of your check valve for specific installation instructions. Here are some general check valve installation guidelines.

RPZ backflow preventers are designed to prevent contaminated water from mixing into clean municipal water supplies and are commonly used by municipalities, homes, and commercial buildings. These valves provide reliable protection against back pressure and siphonage, safeguarding water supplies from any form of contamination.

Check valves can be installed at the service entrance or at individual water outlets. Unlike atmospheric vacuum breakers, check valves are designed for continuous pressure systems. Some valves can be installed either horizontally or vertically, and others must be installed in one orientation or the other. Swing check valves, for example, cannot be installed vertically. Horizontal installation is preferable because gravity will not affect a check valve’s performance. However, you should install your check valve in the orientation it was designed to work in.

You must have a backflow preventer installed at the water meter if you have an irrigation system or get your water from a well. If you have recently noticed discoloration, sulfuric smells, or bad taste in your water, you will want to get your system checked by a plumber. Even if your water does not show any of these signs, backflow prevention devices are recommended anywhere that potable and non-potable water lines connect. If you do not have backflow prevention devices installed, the purity of your drinking, cooking, and cleaning water is put at risk. If pressure changes in your system and you do not have a preventer, you are at risk of backflow.

Many factors can cause a backflow prevention device to leak, so you must first identify the cause before you attempt to fix your preventer. If an air gap leaks, it may be doing its job. It also may have been installed incorrectly, or there could be an issue with the drain line.

Vacuum breaker installation is extremely straightforward. To install an AVB, simply screw the breaker onto your hose, faucet, or spigot. Ensure that the size of the breaker you purchase matches the size of the system you wish to connect to. Most vacuum breakers come with a locking feature that prevents the connection from separating.

Check valves are devices that ensure water flows in only one direction. They open and shut based on the pressure on both sides of the valve. When pressure is higher on the incoming side than the outgoing side, the valve is open, and water can flow like normal. When pressure is higher on the output than the input, the valve shuts, eliminating the risk of water being pulled into the clean water line.

Improper installation of a backflow prevention device can also cause leakage. Preventers are easy to install incorrectly, and small mistakes can cause your device to malfunction. A common mistake when installing a backflow preventer is overtightening the head assembly. Always tighten the head assembly by hand so that it does not overtighten. Overtightening can damage the seal of the device and necessitate the washer being replaced. You must also ensure that the device is installed in the correct direction. Since backflow preventers force water to flow in only one direction, installing it backwards eliminates its usefulness.

Reduced pressure zone assemblies, also commonly referred to as reduced pressure zone (RPZ) valves or RPZ backflow preventers, are an essential system that prevents the backflow of clean water to avoid contamination.

Rapid and unexpected reduction of pressure in pipelines can present an extreme risk of contamination to water supplies. When water pressure goes down, water flows in the wrong direction, bringing contaminated water from home appliances and other industrial processes with it. Even the slightest fluctuation in pressure can cause backflows and contaminations.

Air gaps are used in sinks to prevent debris from entering drinking water or a dishwasher. They are a literal gap of air between the water outlet and flood level of a dishwasher. Air gap devices are used to prevent backflow with air gaps. They are generally inexpensive and come in a variety of materials and finishes. Air gaps eliminate contamination risk by separating the hose that runs dirty water and the hose that runs to the drain. Air gap devices separate these two hoses, making contamination impossible because these hoses never intersect.

AVBs must be installed at least six inches above ground to be effective in preventing backflow. If air contaminants are present, they can enter the AVB and contaminate the pipes. AVBs are not effective in a consistent pressure water system and should not be placed upstream of a shutoff valve.

The Department of Health made it mandatory that all water systems that provide water for nonpotable use should use backflow preventer systems such as the RPZ. This means that public water supplies, commercial property owners, and residential property owners should install backflow systems to protect users from health hazards that can result from water contamination.

Old parts in a backflow preventer must be replaced over time to avoid leakage. If your device is leaking, check the washer in the seal. If the washer is deteriorated, simply replace it to repair the seal.

Whether you are a municipality or a property owner, complying with Illinois’ backflow protection codes means installing a robust backflow prevention system. Thankfully the team of experts at Dahme Mechanical Industries is fully certified and able to perform RPZ backflow prevention installation, testing, calibration and repair. We serve Arlington Heights and the surrounding communities, including Schaumburg, Des Plaines, Palatine, and more. Contact us today to learn more!

Because of fluctuating pressures, designs should factor in the intensity and frequency of the fluctuations. For instance, installation of a single-check valve upstream of the RPZ valve prevents fluctuation of pressures upstream, which are usually the primary cause of frequent discharges through the relief valve.

Immediately after installation, you can expect a small amount of water to come out of your backflow prevention device. If your backflow preventer drips constantly, there is a leak that needs to be addressed.

Backflow prevention leaks can be caused by many factors, and some are more preventable than others. Here are some common causes of backflow prevention device leaks.

Modern plumbing codes require backflow prevention to be installed wherever a cross-connection exists. If the plumbing in your home is old, you are at greater risk of having no backflow prevention systems installed.

Back pressure results from wastewater systems with higher pressure than the incoming fresh water supply. Problems within the sewer line can cause pressure to increase and lead to back pressure, but the most common source of back pressure is a pressure decrease in the supply line. Back pressure most often occurs in pressurized systems, such as elevated tanks, pumps, or boilers. Sprinkler systems and power washers can also fall victim to backflow via back pressure.

Only a certified assembly tester should perform the RPZ backflow preventer test, using a properly calibrated tool. Testing procedures may vary from state to state, but it must comply with the Department of Health and Illinois Plumbing Codes. Building maintenance workers, contractors, and plumbers use RPZ testers to measure the pressure difference between two points.

Unless the valve is specifically approved for vertical installations, RPZ valves should be installed horizontally with the relief valve mechanism discharging downward. In order to prevent any fouling of the RPZ assembly elements, plumbing engineers should install in-line strainers upstream of the RPZ valve. The valves must be installed above the floor surface to facilitate easy and fast inspection, testing, and maintenance.

When installing RPZ valves, contractors should avoid installing them in areas prone to flooding, places above electrical equipment, and positions that expose the valves to mechanical damage. The area should also be in a heated enclosure to prevent freezing, which can lead to ice buildup inside the valves, which can block water from flowing.

A backflow prevention device works by prohibiting wastewater from reversing into the supply water line. How a specific backflow prevention device works depends on the application it is used for, as they each employ unique mechanics to protect the clean water from contamination. Below you can find how air gaps, vacuum breakers, and check valves operate to eliminate backflow.

When there is a water leak in your supply lines, hydrant flushing, city water main break, or use of hydrant to fight fire, pressure in the water system drops. When this occurs, a RPZ prevents backflows, effectively preventing clean water from backing up to supply systems hosting potential contaminants.

Backflow preventers should be tested yearly for wear and defects. All businesses are required by law to have backflow prevention devices tested yearly, and homes are subject to testing based on local legislation.