By Pacific Heating & Cooling | Certified Plumbers | Updated September 2026

If you clear a clogged drain and it backs up again within a few days or weeks, the problem is not the clog itself. It is whatever keeps causing it. A drain that keeps clogging is usually the result of a partial blockage further down the line, grease or soap buildup that keeps narrowing the pipe, tree roots growing into an underground line, or a venting issue that keeps waste from draining fully. Here is what typically causes repeat clogs, what you can safely check yourself, and when the situation calls for a plumber instead of another bottle of drain cleaner.

The most common causes of a drain that keeps clogging

Most repeat clogs trace back to one of five things. A single plunge or a bottle of drain cleaner might clear the symptom for a day or two, but if the underlying cause is still there, the clog comes right back.

Grease, soap, and hair buildup further down the line

This is buildup that has narrowed the inside of the pipe well past where a plunger or a store-bought drain cleaner can reach. You will notice water draining slower over several weeks rather than stopping all at once, along with a clog that seems to clear briefly and then return. A technician clears this with a drain snake or cable that reaches past the buildup, and in more stubborn cases, hydro jetting to scour the inside of the pipe clean.

Tree root intrusion in the sewer or drain line

Tree and shrub roots naturally seek out moisture, and older clay or cast iron lines, common in many Western Washington homes, give them small gaps to grow into. You will usually notice slow drains at multiple fixtures at once, gurgling sounds, or a clog that returns every few months on a predictable cycle.

A venting problem in the plumbing system

Every drain line relies on a vent stack to let air in so water can flow out smoothly. When a vent is blocked or was installed incorrectly, drains gurgle, drain slower than they should, and clogs seem to come back even after a fixture is cleared. A technician checks the vent stack, often from the roof, and clears or corrects it so the drain can work the way it was designed to.

An old, bellied, or damaged pipe

Pipes that have settled, sagged, or corroded over decades create a low spot where water and debris collect no matter how often the line is cleared. This shows up as a clog that returns in the same spot again and again, often with a gurgle or slow drain that never fully resolves. The fix usually starts with a video inspection to locate the damaged section, followed by a targeted repair or a section replacement.

What a homeowner can do vs. what requires a plumber

What you can safely check yourself:

  • Use a plunger on the affected fixture before trying anything else
  • Remove and clean visible debris from a sink or tub stopper
  • Run hot water for a minute or two to see if a partial clog clears on its own
  • Avoid pouring grease, coffee grounds, or wipes down the drain going forward

What calls for a plumber:

Repeated chemical drain cleaner use can actually damage older pipes and does not address a blockage that is further down the line, growing roots, or a vent problem. A plumber uses a visual pipe inspection to see exactly what is happening, then chooses the right tool, whether that is a cable, hydro jetting, or a targeted repair, based on what is actually causing the clog.

Signs you should call a plumber for a recurring drain clog

A single slow drain is often something you can handle yourself. These signs point to something a plumber needs to look at:

  • More than one drain in the house backs up around the same time
  • You hear gurgling from a toilet or another drain when you run the washing machine or dishwasher
  • The same drain clogs again within a week or two of clearing it
  • Water backs up into a tub or shower when another fixture is in use
  • You notice a sewage smell near a floor drain, basement, or crawlspace
  • Sinks and toilets across more than one room are all draining slowly

Pacific Heating & Cooling’s clogged drain service in Tacoma starts with a real diagnosis, not a guess, so you know exactly what is causing the backup before any work begins.

What does it cost to fix a drain that keeps clogging?

Pacific Heating & Cooling technician clearing a drain clog with a cable machine

A Pacific technician clears a drain clog with a cable machine, reaching past the buildup a plunger alone can’t touch.

The honest answer is that it depends on the cause, not the symptom. A simple buildup clear near the fixture costs far less than a video inspection and root cutting on a main line, or a targeted pipe repair. What we can tell you clearly is how we price it: no-surprise, upfront pricing before any work begins, so you know the cost of the actual fix, not just a service call.

Because Pacific does not yet have a full year of drain clog job records in our service system to publish a specific cost range for this service, we are not including a dollar figure here. Once that data is available, this section should be updated with a real range based on completed jobs, following the same standard used for our HVAC repair posts.

Most drain clog visits are completed the same day, and if a video inspection uncovers a larger issue like root intrusion or a damaged pipe, you will see what we see and understand your options before we move forward.

FAQ: Common Questions About Clogged Drains

Cost depends on the cause, not the clog itself. Clearing buildup near a fixture costs less than a video pipe inspection with root cutting or a pipe repair. Pacific provides no-surprise, upfront pricing before any work begins, so you know the exact cost of your specific repair before agreeing to it.
 

A drain that clears and clogs again within days is not an emergency, but it is a sign the underlying cause has not been fixed. If more than one drain backs up at once or you notice a sewage smell, treat it as urgent and call a plumber right away instead of waiting.
 

If a drain keeps coming back after you clear it yourself, a plumber’s video inspection tells you exactly what is happening inside the line instead of guessing. That upfront diagnosis is what stops you from paying to clear the same clog every few months.

If a drain keeps clogging in the same spot, the clearing method used only removed what was blocking the surface, not the actual cause further down the line. Common culprits are buildup past where a plunger reaches, root intrusion, or a bellied section of pipe that collects debris no matter how often it is cleared.

Yes. Roots grow toward moisture and can enter through small cracks or joints in older clay or cast iron lines, which are common in many Western Washington homes. Once inside, roots create a snag that catches debris and causes the same drain to clog again on a repeating cycle.

Drain cleaning with a cable or snake breaks through a clog and creates a path for water to flow again. Hydro jetting uses high-pressure water to scour the entire inside of the pipe clean, which is a better long-term fix for buildup that keeps coming back.

Repeated use of chemical drain cleaner can damage older pipes and does not fix the actual cause of a recurring clog, such as roots or buildup further down the line. If a drain needs more than one treatment to stay clear, it is time for a plumber to find out what is really going on.

Still not sure what’s causing the problem?

Tell us what your system is doing and we’ll help you figure out the right next step. Pacific Heating & Cooling has been diagnosing heating and cooling problems across Tacoma and the South Sound since 1984. NATE-certified technicians, 2-hour arrival windows, and upfront pricing before any work begins.


(253) 248-6260

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