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Is Your Clean Water Getting Contaminated by Your Air Valves?

Av-Tek Valve's Air Valve

Did you know that the air valves in your water treatment system may contaminate your water supply? 


In this blog, we’ll explore the role of air valves in water systems and discuss potential issues that may arise if they’re not properly maintained. We will also provide tips for choosing the right valves and what can be done to prevent contamination from happening.


At Av-Tek Valves, we manufacture high-quality and durable valves. Our team is committed to providing you with the best products and services to create quality solutions for your community. Call us at (385) 325-2504 or (801) 637-8541 or leave a message here to learn more.


Can Your Clean Water Get Contaminated by Air Valves?


The design of air release valves can significantly affect the potential for water contamination. Air valve exhaust pipes often have a full column of stagnant water in them from when the valve is exhausting air when the pipeline is filling up. 


This is because most air release valves seal around 25 – 30 psi unless a special soft seat is provided. So when the pipeline is filling and pressurizing, your air valve is exhausting both air and water into the exhaust pipe.  


This stagnant water is a breeding ground for contaminants such as E. coli and cryptosporidium. Then when vacuum conditions occur, this water and all the contaminants are sucked back into the system.  This can be extremely harmful or even toxic and can potentially compromise the integrity of the water supply. 


This is a water sample from inside a large bowl type air valve after the pump was running for about two weeks.


After a combination air valve failed, this water district set out to find the cause. Because the water in the valve had never circulated, all the contaminants collected in the high point of the pipe, known as the air valve!


By reducing the size of the valves, we can minimize the potential threat from stagnant, infested water in the bowl of the valve. As the pipeline is under pressure, the water in the air valve does not circulate, thus creating stagnant water in the valve body.  


Av-Tek’s 3” and 4” Ductile Iron Air Valves have drains in the bowl and a solenoid or ball valve can be added to drain the bowl.  This will help keep the water inside the valve fresh.  


Av-Tek’s ductile iron air/vac valve design is such that the air exhaust comes out of the valve at a 90° angle rather than straight out of the top. This keeps the water off of the sealing surface of the valve.


Inside the exhaust section of an Av-Tek valve, there is also an integral drain, so the water that is exhausted out of the pipeline with the air will drain out of the exhaust port. This ensures you will never suck back in stagnant water that is typically in an exhaust pipeline. 

Av-Tek’s Air/Vac Valve, showing the drain port on both
the bowl and the exhaust port.


What Do Air Valves Do?


Air valves help control airflow in water systems. 


Air valves, air release valves, Air/Vac valves and combination air valves serve several important functions, including; air release during pipe filling, air vacuum during pipe dewatering, and air release under pressure. They are essential for the efficient operation of a water system.


Air valves contribute to the overall integrity of the water supply in several ways:


1. They remove air from the system


Air release valves are designed to release air from the system. They allow air out when the pipeline is filling up, as well as release air pockets that can accumulate in the lines. These air pockets can hinder the efficient flow of water through the system. 


In extreme cases, they can cause a vapor lock impeding all passage of media through the pipeline. Releasing the air pockets also helps to prevent water contamination, as oxygen accelerates the growth of many contaminants. 


2. They maintain water pressure


Proper water pressure is essential for maintaining equilibrium within the distribution system. When excess air builds up in the pipes, it can cause water pressure to drop and lead to reduced water flow and potential outages. Air valves release excess air, allowing the media to flow unimpeded through the system.


3. They protect pipes from damage


A primary function of air valves is to allow air into the system in the event of a vacuum. Without this function, pipelines can be crushed and destroyed by the negative pressure caused by a vacuum. Air valves also eliminate air pockets in pipelines which can accelerate corrosion. 


How to Select the Right Air Release Valves


High-quality air valves are more reliable and less prone to leaks or malfunctions. This means that they are more effective at maintaining proper water flow, pressure, and cleanliness, which helps secure the overall quality of the water supply. 


When selecting air release valves, there are a few things to consider.


1. Materials


The material used in the construction of air valves can impact their durability, performance, and cost. Some materials are more resistant to wear and corrosion, increasing the longevity of the end product. 


The material can also affect the valve’s performance, such as its resistance to high temperatures or pressure.  It is highly recommended that ductile iron or polyamide (PA) is used due to its strength. 


Cast iron easily cracks and fails when there is variation in temperature.  It is also recommended, when using ductile iron to use fusion bonded epoxy inside and out along with stainless steel internal components.  This helps prevent build up and corrosion. 


2. Specifications


The flow rate and pressure range of the valve should be appropriate for the specific needs of the water system. Otherwise, it may not function properly and could potentially cause issues with the water supply. 


Other specifications, such as the size and connection type of the valve, should also be taken into account to ensure that it is compatible with the existing system. 


3. Maintenance Requirements


Air valves that require frequent maintenance can be time-consuming and costly to keep in good working order. By choosing valves that have low maintenance requirements, it is possible to minimize the amount of time and resources that are needed to keep them functioning properly. 


Plus, valves that are easy to maintain may be more convenient to work with and may be less prone to errors or issues during maintenance.  


One overlooked maintenance point are the stems or linkage systems. Av-Tek does not use guide stems or linkage systems in our valves for this reason.


Choose Av-Tek’s Air Valves


Av-Tek Valves are a top choice for municipalities and industries seeking reliable and high-quality valve solutions. We offer a wide range of air valves, making it easy for you to find a valve that meets your specific needs.


Here are a few of our most popular air valves:


1. Ductile Iron Valves: With the Av-Tek series 5300 valves, you will never have to worry about exhausted water coming back into your system when a vacuum occurs. With a drain port cast into the exhaust vent, simply attach a drain line with an isolation valve or check valve.


2. Poly Air Valves: These modern valves are reinforced with Polyamide (PA) Fiberglass, which allows them to handle extreme conditions. They’re lightweight, easy to maintain, and highly durable.  The 1” valve has a pressure range of 3 psi to 350 psi without modifications and our 2” valve has a pressure range of 7 psi to 250 psi.


3. 5500-02 Wastewater Air Valves: Significantly smaller and lighter than most wastewater combination air valves.  The 5500-02 Wastewater Air Valves’ simple design helps to prevent failures and makes them easy to maintain.




Air release valves play a crucial role in maintaining the cleanliness and purity of your water supply. To ensure that your water stays clean, it’s important to invest in high quality air valves that are able to effectively prevent water contamination, maintain proper water pressure, and protect your pipes. 


By choosing only high-quality air release valves, your water stays clean, and your system will always function properly and efficiently.


Reach out to Av-Tek Valves for all your questions regarding air valves and other valves. To learn more, you may contact us at (385) 325-2504 / (801) 637-8541 or leave a message here.

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