Why Your Drains Keep Clogging

A drain that clogs once is a clog. A drain that keeps clogging is telling you something further down the line.

Where it builds up, and from what. In the kitchen it's grease — it goes down liquid and sets solid somewhere cooler along the pipe, then catches coffee grounds and food scraps on the way past. In a tub or shower it's hair bound up with soap scum. In a toilet it's wipes, paper towels, and things that were never meant to go in at all: toothbrushes, combs, the occasional action figure. Those rarely make it past the first turn.

First, don't reach for chemical drain cleaner. It frequently doesn't clear the blockage, it can damage the pipe, and it leaves standing water that's hazardous to whoever opens that drain next. We once pulled a section of PVC that a drain cleaner had cooked — the reaction generated enough heat to deform the pipe, and what came out looked more like wire on a telephone pole than a drain line. If you have already used one, tell us when you call. We can usually smell it, but we'd rather hear it from you first.

One fixture, or several? This is the question that tells you how big the problem is.

• One fixture, clears and comes back. Buildup in that branch or its trap. Usually within reach.

• Several fixtures at once — especially if the lowest drain in the house is first to back up. That points at the main line.

• Gurgling somewhere else when you run this one. Air is finding its way through the wrong path. Either a partial main blockage or a venting problem.

• Slow and gurgling, but not actually blocked. Often venting rather than a clog. Vents let air into the drain lines so water can move; without that air, drains run slow and noisy, and a trap can siphon dry.

What's different about older houses. A lot of homes around here still have cast iron, galvanized or ABS drain lines. Cast iron and galvanized scale up from the inside, narrowing the pipe until what used to pass no longer does. Hairline cracks in cast iron and ABS are hard to see, even with a camera. And underground lines that have degraded let tree roots in — that's a clog that comes back every year like clockwork until the line is replaced.

One cause nobody guesses. High-efficiency furnaces and boilers produce acidic condensate, and it eats drain lines from the inside out. We've pulled copper condensate drains that felt like foil at the cut edge. If you have condensate drains, the acid neutralizer mix needs replacing annually — it raises the pH of the condensate and stops the corrosion.

What should actually go down a drain. Wastewater, human waste and toilet paper. That's the whole list. Grease, food scraps, "flushable" wipes and chemical cleaners account for most of the rest of our calls.

When to call us. Several fixtures backing up at once. A clog that returns within weeks. Gurgling, odors, or slow drainage across the house. Any of those means the problem is past where a plunger reaches.

One honest note. We don't do camera inspections or drain cleaning in-house. We work with specialists we trust and bring them in when a job needs it — and we handle the repair and replacement side once we know what we're dealing with.