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How Do I Unclog a Roof Vent?

Unclog a Roof Vent

You might need to run a drain cleaner through your roof vent if it's clogged, or if this is the easiest way to access a clogged main drain.

Slow draining and gurgling plumbing fixtures could be a sign of a clogged roof vent. And, on homes that do not have a main drain cleanout, accessing a clogged main drain through the roof vent could be your best option.

  1. Start by trying to clean the roof vent and main drain with a hand held drum auger.
    • Important: before you attempt any work at roof height, take into account the accessibility and condition of the roof, the weather conditions, and any other factors that might complicate the job. Do not try this approach if you have no experience working on high ladders or aren't comfortable with the project.
    • Avoid working on wet or snowy roof surfaces. You should wear rubber-soled boots or shoes, use ladders and other equipment that are in good condition, and use a roof harness if needed to assure your safety. And, if you're concerned about completing the job safely, consider hiring a licensed plumber to help.
    • To use the hand held drum auger:
    • Read and follow the auger safety instructions, then put on work gloves and eye protection.
    • Start by feeding the auger a short distance into the vent to check for an obstruction close to the vent opening that you might be able to pull out.Handheld Drum Auger
    • Next, try to feed the auger its full length int the vent stack, through to the main drain, by locking the cable, turning the drum in a clockwise direction, and then unlocking and feeding the cable as needed to pass the auger tip through any elbows and blockages.
    • After you have inserted the drum auger its full length, pull out the auger cable as you feed it back into the drum. It may take several attempts to remove most of the blockage.
    • Note: if you can't reach the clog with a hand held auger, you can try a flat sewer rod with a disk-shaped tip that can usually pass through more types of small diameter elbows and transitions, and is sold in lengths up to 100 Ft.
    • You can check if the clog has cleared by inserting a garden hose down into the vent opening, asking a helper on the ground to turn on the water, and seeing if the water flows freely down through the main drain. However, if the vent or main drain is still clogged, this could cause dirty fluid to flow out of indoor fixtures that are connected to the vent or drain.
  2. Needle Nose Drain CleanerIf there is unusually stubborn debris clogging the vent, or if the main drain is clogged, you might be able to flush out the debris with a sewer jetter.
    • A Needle Nose™ drain cleaner is a sewer jetter with a tougher, braided steel jacket and a special compact nozzle tip that allows it to pass through almost as many pipe elbows and transitions as a hand-held auger.
    • Note: you can read several success stories on our Customers Page from people who cleared a clogged main drain by feeding a sewer jetter through a roof vent.
    • Important: you should consider using a sewer jetter to clean through to the main drain only if the hand held auger easily passed its full length through the stack, since the jetter cannot pass through as many elbows and transitions as the hand held auger.
    • You will need help from someone on the ground to stay near the pressure washer, control the trigger, feed up the sewer jetter hose, and guide the hose to avoid snagging it on gutters, flashing, and other objects.
    • Throughout the process you should carefully position the sewer jetter hose so that it cannot pull itself to the ground, being cautious not to trip or get snagged on the line as you move about the ladder and roof.
    • Needle Nose Drain CleanerTo use the sewer jetter:
    • Put on fluid resistant work gloves and eye protection, and then guide the nozzle at least a foot into the vent opening before you start the flow of water.
    • Guide the sewer jetter through the vent stack to the main drain as you squeeze the trigger. For more thorough cleaning, every few feet pull back about halfway and then continue moving forward.
    • After you have finished cleaning the line, pull the drain cleaner out. Use care to stop the flow of water before the nozzle reaches the vent opening.
    • To check for a cleared line, insert the garden hose down into the roof vent opening, ask a helper on the ground to turn on the water, and watch to see if water seems to be flowing freely into the main drain.
  3. If you're not comfortable performing any of these steps, hiring a good, licensed plumber could save you money in the long run. To find a good plumber in your area:Licensed Plumber
    • Start by asking family, friends and co-workers to recommend a licensed plumber who has performed similar services for them.
    • If you are unable to find a good recommendation from someone you know, search local directories like Google Maps, Yelp and CitySearch for licensed plumbers nearby who have good online reviews. Don't always trust reviews from individuals who published very few other reviews, or from people who give only positive reviews to everyone. Be aware that good service providers sometimes get a small number of negative reviews for reasons that might not be relevant to your situation. Look for a company with several reviews that tell a positive, believable story about repairs that are similar to yours.
    • After you find one or more licensed plumbers who seem to have a good reputation, search online for the company name and the names of individuals at the company, if known. Take into account both the positive and negative information that you find about the company.
    • Be aware that good plumbers sometimes have a backlog of several days during peak times when there are low temperatures, heavy rainfall or holidays. Sometimes heavy demand can be a sign of a company with lots of repeat customers.

If you have questions or comments please contact us.