If more than one drain in your home is slow or backing up simultaneously, you are not dealing with an ordinary clog. Here is what that pattern means — and why it is more common in older Tacoma and Pierce County homes than most people realize.
Published September 3, 2026 • By D Street Drain Cleaning • Tacoma & Pierce County
When a single sink or shower drains slowly, the clog is almost certainly right there at the fixture level — hair, soap scum, food debris stuck in the branch line. That's annoying but contained. You can often clear it yourself.
But when multiple fixtures back up at the same time — two sinks, a toilet, and a shower — that pattern means something entirely different. All of your home's drains converge into one pipe: the main sewer lateral. That pipe runs from your house underground to the city sewer main in the street. When there is a blockage or restriction in that main lateral, wastewater has nowhere to go. It backs up simultaneously into every drain it can find, starting with the ones lowest in your home.
This is not a problem a plunger fixes. It is not a job for store-bought drain cleaner. It requires a professional with the right tools to locate and clear the blockage in the main line.
In Tacoma and Pierce County, the main sewer line problems we see most often fall into a few categories:
This is the number-one culprit in pre-1970 Pierce County homes. Older sewer laterals were built with clay tile pipe — short sections of fired clay laid end to end with open joints, designed to let groundwater drain away from the pipe. The problem is that tree roots find those joints too.
Tacoma's tree canopy is dense. Big Leaf Maple — the most common large native tree in the South Sound — has an aggressive, shallow root system that naturally gravitates toward moisture. Once a fine root tip finds a clay joint gap, it grows inside the pipe, branches out, and catches every piece of debris that comes through. Over months or years, that root mass grows until it restricts flow enough to cause backups under normal household water use.
Neighborhoods like South Tacoma, Proctor, Stadium District, Hilltop, and the North End — where mature trees line residential streets and most homes were built before 1965 — have the highest concentration of this problem in Pierce County. If your home is on a street lined with large maples or cottonwoods and your main line has never been cleaned or inspected, there's a reasonable chance roots are already inside.
Cast iron pipes — common in Tacoma homes from the 1950s and 1960s — develop a rougher interior surface as they oxidize over time. Grease, soap, and particulate matter adhere to that surface and build up over the years. Unlike the acute blockage from roots, grease accumulation is gradual: drains get slower and slower until eventually the line is restricted enough to cause simultaneous backups under heavy use (running the dishwasher and laundry at the same time, for example).
A pipe belly is a low spot where soil beneath the pipe has shifted and the pipe has sagged downward. Tacoma's glacial till soil — dense but not uniformly stable — can shift subtly over decades, particularly on hillside lots common in neighborhoods like the Stadium District, North End, and areas near Tacoma's steep bluffs. Solids collect in the belly instead of flowing out, and eventually that accumulation blocks the line. Bellies do not clear themselves; they require camera inspection to locate and either repair or reline.
Clay tile and cast iron pipe have a finite lifespan. A line that has been in service for 60 or 70 years may develop cracks from ground movement, root pressure, or corrosion. A partially collapsed section narrows the flow area dramatically. In worst cases, the pipe fails entirely and sewage has no path to the city main.
"Flushable" wipes — which are not actually flushable in older clay or cast iron lines — are a growing cause of main line blockages in older Pierce County neighborhoods. They do not break down the way toilet paper does. Combined with root intrusion or existing debris, they form dense clumps that fully block flow.
Before calling a drain company, you can run a quick diagnostic to confirm the problem is in the main line. This also helps the technician when they arrive.
October through March is when most of the main sewer line failures in Pierce County become emergencies. Here is why:
A partial main line blockage that drains slowly in July may be a full backup emergency in November. If multiple drains in your home have been getting progressively slower over the past few months, do not wait for the rain to arrive. Schedule a camera inspection now, when it is a planned visit instead of an emergency call.
One thing that surprises many Tacoma homeowners: you are responsible for the sewer lateral from your house all the way to the city main in the street. The city maintains only what is inside the main — everything from your foundation to where it connects is on you. This is called the side sewer, and it runs anywhere from 20 to 100 feet depending on your lot and street layout.
If the blockage is in the city main itself, the city will clear it at no cost. But in the vast majority of cases, the problem is in the homeowner-owned lateral — roots at a clay joint, grease at a belly, a cracked section. Understanding this before you call helps set expectations. D Street will tell you exactly where the blockage is and whether it is in your section of pipe.
Learn more about how side sewer responsibility works in Tacoma: Side Sewer Tacoma — What Homeowners Are Responsible For.
We serve Tacoma, Fircrest, Lakewood, University Place, Puyallup, Federal Way, and surrounding Pierce County communities. Same-day service available for urgent situations. For non-emergency inspections, we typically schedule within 48 hours. D Street Drain Cleaning — (206) 948-0851.
Same-day service for main sewer line issues throughout Tacoma and Pierce County. We run the camera first — you see what we see before any work is approved.
Related: 10 Signs Your Main Sewer Line Needs Service in Tacoma • Sewer Camera Inspection — What to Expect • Hydro Jetting Service