What Are Anti-Siphon Hose Bibs?

Clean water is an essential part of a healthy community. There are many steps that must be taken in modern plumbing to ensure that dirty water does not get mixed with clean water. Anti-siphon hose bibs are one of the solutions for preventing the contamination of clean water sources. Newer outdoor faucets, also known as spigots, have an anti-siphon valve built in that helps ensure that dirty water or contaminants do not get sucked back in through a garden hose. You may hear them referred to as back flow preventer hose bibs as well because they are hose bibs with a built-in back flow preventer. Typically, you will find anti-siphons installed on faucets where you would attach a hose, so think outdoor spigots or utility sinks. 

Why Does Water Siphon? 

You may be thinking that when you turn on your spigot, water only flows one way - out. However, this is not always the case. Your home’s plumbing is based on a system of pressure, and that pressure varies based on the supply, temperature, and many other factors. Changes in pressure can cause some amount of water to be pulled back into the line any time a hose is attached to the water supply. This process of water being sucked back into a line is referred to a siphoning. This is why anti-siphon valves are very important to have on any water source that you may attach a hose to, such as spigots and outdoor utility sinks. 

Let’s go over a few real-life examples where an anti-siphon hose bib would be helpful to better understand the process of siphoning. In the first example, let’s say a garden hose gets left in your yard and water accumulates. You are at risk of dirty water from your yard siphoning and getting sucked back into the hose, and possibly contaminating your clean water. The concern here becomes greater when you factor in chemicals, pesticides, fertilizers, or animal feces that may be in your yard. You definitely would not want these substances coming in contact with the clean water you use throughout your home for drinking, bathing, laundry, and cleaning dishes. Another example would be if your garden hose ends up in your swimming pool while it is still attached to your spicket. It could create a vacuum like system that would pull chlorinated pool water back into the hose and mix with your home’s clean water supply.

Both risks in these scenarios, and many others, are minimized by an anti-siphon hose bib. The built-in back flow preventer will close off the water flow whenever water pressure drops, which prevents dirty water from being sucked back into the clean water supply. 

Do I Need an Anti-Siphon Hose Bib?

Clean water is an essential part of our modern society as it helps reduce the spread of many diseases and illnesses. Because it is so crucial to the health and safety of communities, Federal Housing Codes require homes to have anti-siphon valves. This means that when new homes are built, hose bibs and outdoor faucets must have an anti-siphon valve to pass most local plumbing codes. That being said, hose bibs don’t last forever and are prone to damage, just like other fixtures in your home. It is important to regularly inspect your spigots for leaks, cracks or seal damages that can be caused by age or weather. It is also important to check older homes that were built before current codes were in place. If you live in a rural area, it is also possible that your home does not have anti-siphon valves because the codes are a little less stringent than in urban areas. 

Anti-Siphon Hose Bib Install in Austin, TX

Not sure if you have anti-siphon hose bibs? Live in an older home, or concerned about the quality of your water? The easiest way to know if your home is up to code and has the proper anti-siphon valves is to schedule a visit with one of Stan’s licensed plumbers. We will be able to quickly inspect your spigots and utility sinks to determine if you are up to code. If we find that you are not, adding the anti-siphon valve, or upgrading to anti-siphon hose bibs and faucets, is a quick and affordable fix! Contact Stan’s today to make sure the quality of your water is not at risk of being compromised! 

Request Your Service

Online requests are processed
Mon-Fri: 7am-5pm and Sat 8am-12pm.

How Can We Help You?

Choose Your Service Below

How Can We Contact You?

Enter your full name
Enter your phone number
Enter your email address


Enter your address
Enter your city
Enter your state
Enter your city
Please note, ability to honor requested service date is subject to availability. A Stan’s customer service team member will contact you to discuss availability.
By submitting this form and signing up for texts, you consent to receive marketing text messages (e.g. promos, cart reminders) from Stan's Heating, Air and Plumbing at the number provided, including messages sent by autodialer. Consent is not a condition of purchase. Msg & data rates may apply. Msg frequency varies. Unsubscribe at any time by replying STOP or clicking the unsubscribe link (where available). Privacy Policy.


Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.