Why Does My Drain Keep Clogging? 6 Common Causes (and How to Stop It)

Published July 8, 2026 · Snake-It-Away Inc.

If you've plunged the same sink three times this month, the problem isn't bad luck. A drain that clogs over and over is telling you something: the clog you keep clearing is a symptom, not the cause.

We've been clearing drains around the Boston metro since 1997, and the same handful of culprits come up again and again. Here's what's usually going on.

1. Grease and fat buildup

Kitchen drains clog more than any other line in the house, and grease is why. It goes down warm and liquid, then cools and hardens on the pipe wall a few feet in. Every clog you clear leaves a little more behind, so the gap gets narrower each time. Pouring boiling water down helps for a day. It doesn't remove the layer that's already set.

2. Hair and soap in bathroom lines

Shower and bathroom sink drains collect hair, and hair grabs soap scum. The result is a mat that water squeezes through until it can't. A drain cover helps going forward, but once the buildup is coating the pipe, you need it physically cleared.

3. "Flushable" wipes (they aren't)

Wipes don't break down like toilet paper. They snag on any rough spot in the line and catch everything behind them. If a toilet clogs repeatedly, wipes are a prime suspect.

4. Old pipes with rough interiors

A lot of homes in Medford, Somerville, and the older parts of Boston still run on cast-iron or clay drain lines. Over the decades the inside surface corrodes and gets rough, and rough pipe catches debris that smooth pipe would carry away. That's why an older home clogs more often than a new build, even with the same habits.

5. Tree roots in the sewer line

If it's not one fixture but the whole house draining slowly, roots in the main sewer line are a common cause in our leafy suburbs. Roots find the tiny gaps in older pipe joints and grow into the line. Clearing them takes professional root removal, not a store-bought product.

6. A partial main-line blockage

When more than one drain acts up at once, or the lowest drain in the house (often a basement floor drain) backs up, the blockage is usually in the main line that carries everything out to the street. Clearing one fixture won't fix it.

How to actually stop the cycle

Repeated clogs in the same spot mean buildup that a plunger or store-bought chemical can't reach. Two things fix it for good:

• A proper cleaning that scours the pipe wall instead of just poking a hole through the clog. Our drain cleaning and, for stubborn buildup, hydro jetting do exactly that.
• A camera inspection when the cause isn't obvious. A camera inspection shows what's really in the line, so you're not guessing.

One note on chemical drain cleaners: they can eat at older pipe and rarely clear a real blockage. We'd skip them, especially in an older home.

Get it cleared right the first time

If the same drain keeps coming back, let's find out why and fix it for good. We're Medford-based, family-owned, and available 24/7 across the Boston area. Call (781) 858-8314 for honest, upfront pricing and a job done right.