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What is Backflow?

In plumbing, backflow can be a serious issue and lead to a huge mess, but what is it? Backflow is when water or sewage backs up into a home or other building. This issue can cause major damage for flooring, drywall, and even cabinetry. In addition to damage that may occur when a toilet backs up, drinking water can become contaminated by unclean water backing up into clean water. Let’s take a closer look at what causes backflow, and then at some ways to prevent it.

What is Backflow?


The most common cause of backflow into a home or business is flooding. Environmental flooding can cause major damage to buildings and structures on its own, but when backflow occurs it can severely damage the interior of a building. In addition to the obvious structural damage that occurs during a flood, backflow can also contaminate water in the home, making it unsafe to consume.

In addition to flooding backflow can also be caused by unsteady water pressure coming into the home. If you’re on city water, you could be affected by things happening throughout your area, such as a water line break or a fire hydrant being used. When pressure drops you are more susceptible to backflow.


Preventing backflow isn’t as complicated as it may seem. A backflow prevention device can be installed to keep contaminated water from coming back into your home. A prevention device can be an air gap or a backflow preventer valve. Both of these can be installed by a plumber and should be inspected on a regular basis.

If you own a newer home it is likely your waterline has an air gap as it is required in many states to pass inspections nowadays. In older homes, you may not have the proper prevention device in place and could run into issues. In addition, a plumber can check your water to see if backflow may be an issue and take the measures necessary to fix the problem before it becomes a bigger issue.

If you are concerned about backflow in your home or place of business, call us at Michael Runk Plumbing and Heating today! We can check your water quality and let you know if you have a backflow problem. If we do find a problem, our team of skilled Eldersburg, MD plumbers can install a backflow prevention device to keep your water safe and your home in tip top shape.

What Our Customers Say

"Great experience. Moved into a new home and experienced major plumbing issues (flooding) the morning after New Years. The plumber arrived that morning within the hour and relieved the issues, also provided some recommendations that benefited us in the long-run."

-Matt Lewis

Get Your Water Flowing Again

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Frederick County: Frederick (21701, 20702, 21703, 21709), New Market (21774) , Mount Airy (21771), Urbana (21704), Ijamsville (21754), Walkersville (21793), Libertytown (21762), Damascus (20872), and more.

Howard County: Clarksville (21029), Columbia (21044), Cooksville (21723), Dorsey (21075), Elkridge (21075), Ellicott City (21043), Fulton (20759), Glenelg (21737), Glenwood (21738), Granite (21163), Hanover (21076), Highland (20777), Jessup (20794), Lisbon (21765), Marriottsville (21104), North Laurel (20723), West Friendship (21794), Woodbine (21797), Woodstock (21163), and more.

Montgomery County: Olney (20832), Damascus (20872), Laytonsville (20882), Silver Spring (20910), Clarksburg (20871), Gaithersburg (20878), Germantown (20876), Bethesda (20816), Chevy Chase (20815), and more.

Baltimore County: Arbutus (21227), Catonsville (21228, 21250), Cockeysville (21030, 21031, 21065), Dundalk (21222), Edgemere (21219), Essex (21221), Garrison (21055), Lansdowne (21227), Lochearn (21207), Lutherville (21093), Middle River (21220), Milford Mill (21244), Overlea (21236), Owings Mills (21117), Parkville (21234), Park Heights (21215), Pikesville (21208), Randallstown (21133), Reisterstown (21136), Rosedale (21237), Timonium (21093), Towson (21204), White Marsh (21162), Woodlawn (21207), and more.

Carroll County: Eldersburg (21784), Finksburg (21048), Hampstead (21074), Manchester (21102), Marriottsville (21104), Taneytown (21787), Union Bridge (21791), Westminster (21157, 21158), Mount Airy (21771), New Windsor (21776), Sykesville (21784), Woodbine (21797), Taneytown (21787), and more.

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Michael Runk Plumbing and Heating