Clogged Drains: Symptoms and Solutions 

Woman looking at pipes under bathroom sink
Ashley deHaan
October 20
4 min read

Key Takeaways

  • Start safe & simple: Use a plunger, clear stoppers and hot water with detergent.
  • Match the symptom to the cause: Gurgling or multiple slow fixtures points to vent or main-line issues, not just a single drain.
  • Prevent and know when to call a pro: Catch hair and grease before it enters pipes, flush lines periodically and call a plumber for repeat clogs, sewage odours or backups in floor drains.

Typical reasons drains get clogged and how to troubleshoot

1. Clogged drainpipes

Causes: Over time, soap scum mixes with hair, skin flakes and mineral deposits to create a sticky film on the pipe walls. That buildup gradually narrows the opening, slows drainage and eventually catches larger debris until water backs up. 

Troubleshooting: 

  • Remove and clean the drain stopper. 
  • Next, try using a plunger, remember to block the overflow drain in the tub or sink to get proper suction. 
  • If that doesn’t work, remove the drain elbow joint and clean it out. 

Prevention: 

  • Clean drain stoppers routinely to prevent clogs and use a hair strainer drain cover to trap hair before it goes down the drain. 

2. Clogged toilets

Cause: Flushing items that don’t dissolve or break apart (feminine hygiene products, cotton swabs, dental floss, diaper wipes). 

Troubleshooting: 

  • Try using a plunger to shoot jets of water to clear the drainpipe. 
  • Next, use an inexpensive hand-powered drain auger to reach between 2 to 5 ft. down the toilet’s drainpipe and break up or retrieve whatever is blocking the pipe. 

Prevention: 

  • Only flush waste and paper that readily dissolves in water. 
  • Clean toilets regularly to keep water flowing smoothly. 

3. Clogged kitchen sinks

Causes: Cooking grease and oil cool and congeal on pipe walls, then detergent scum sticks to that film. Starches like rice and pasta (and even coffee grounds) swell in water, creating a paste that traps other crumbs until a hard plug forms in the trap or horizontal run. 

Troubleshooting: 

  • Run very hot water down the drain to soften the clog, followed by a dollop of dish detergent and then more hot water. 
  • Wait a few minutes, then use a plunger and repeat the hot water. 

Prevention: 

  • Dispose of large amounts of kitchen grease and oil by letting them solidify first in a container. Scrape the mess into a plastic bag, seal it and throw it out with the garbage. 
  • Small amounts of oil (less than one cup) should be thoroughly diluted with hot water and dish detergent before being poured into the sink. 
  • For ongoing clogged or slow drains, have a plumber inspect the plumbing to determine if the drain line was properly designed and installed. Both drainpipe venting and slope affect how well drains work. 

4. Clogged vent pipe

Symptom: The sink gurgles when you flush the toilet; tubs or showers drain slowly after another fixture is used, and you may notice intermittent sewer odours near a drain. 

Cause: The vent stack or air admittance valve isn’t letting enough air into the system. That negative pressure can pull water out of traps and slow — or even stop — drainage. Common culprits include bird nests, leaves, ice/snow buildup or a failed auto‑vent under a sink. 

Troubleshooting: 

  • Check that nothing is blocking the vent pipe opening on your roof, like a bird or animal nest. 
  • Check under sinks for gulp valves, typically mounted at the end of a drain line — they look like a plastic cap from a can of spray paint. (The valve prevents sewer gas from escaping the drain line but lets air into the vent pipe when there’s enough suction.) 
  • Fill the sink with water and then drain it out all at once. You should hear air getting sucked into the gulp valve. If not, the valve might need to be replaced. 

Warning: 

  • Venting allows sewer gases to escape and prevents them from building to dangerous levels inside your home. 

5. Clogged main drain

Causes: 

  • Slope (the downward pitch of a horizontal drain) determines how efficiently wastewater and solids move to the sewer or septic line.  
  • Too much slope: water can run too fast and leave waste material behind. Over time, the buildup forms a blockage. 
  • Too little slope: water and waste pool in the pipe, allowing some waste to settle and form a blockage. 

Troubleshooting: 

  • Remove any blockages with a plumbers’ snake and then flush out the pipe with water. 

Prevention: 

  • Have a plumber install a new pipe set at the proper slope to carry sewage away more effectively. 

 

Clogs usually start small and grow until water has nowhere to go. Work through the simple fixes first and keep up with prevention so the same line doesn’t keep failing. But don’t ignore warning signs like repeated blockages, sewer odours or backups in multiple fixtures—those point to bigger system issues best handled by a licensed professional. Enercare can diagnose the root cause, clear it correctly and help you avoid the mess (and cost) of a full backup. 

If your drains are frequently clogged, consider signing up for a drain and plumbing repair protection plan with Enercare. Our plumbing plans come with unlimited service calls and full coverage on parts and labour*. 

*Guarantee – Parts and labour guarantees apply to repairs completed to resolve to the original problem identified. Any subsequent problems with your equipment are not covered by these guarantees. 

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