Key facts: Emergency Sewer Line Cleaning
- Most of Somerville is served by combined sewers that carry wastewater and stormwater together, and big storms can overload them [1].
- Sanitary sewer overflows, including basement backups, are commonly caused by grease, roots and blockages [2].
- Somerville residents report sewer backups and other water and sewer problems through 311 [3].
- Sewage gases include hydrogen sulfide, which is toxic and has a rotten-egg smell [4].
Two causes, one symptom
Why is sewage coming up through my basement floor drain?
Somerville's sewers were largely laid between the late 1800s and the early 1900s as a combined system, meaning the same pipes carry household wastewater and the rain that runs off streets and roofs [1]. On an ordinary day that flow heads through the regional system toward the MWRA's Deer Island plant. During a heavy storm the pipes can fill to the top. When the street sewer is running full, the water level in it can rise above a basement floor drain, and the path of least resistance becomes your house.
The other cause is local. Your building drain runs under the basement floor and out through the foundation, and the lateral continues under the yard or sidewalk to the street. Older laterals are often clay, with joints that roots can slip into; older building drains are often cast iron that scales inside. Grease, wipes and roots can close either one. When that happens, nothing leaves the building, and the first place wastewater appears is the lowest opening [2].
The two can overlap. A partly blocked lateral copes on dry days and fails on wet ones, which can make it look like a city problem when it is really a private one.
Telling them apart
Clues that separate a city sewer surcharge from a blocked Somerville lateral
| Clue | Leans toward storm surcharge | Leans toward private blockage |
|---|---|---|
| Weather | Heavy rain is falling or just fell | Dry weather, or no recent storm |
| Neighbors | Others on the street report backups | Only your building is affected |
| Trigger | Water rises with no one using fixtures | Water rises when someone flushes or showers |
| After the rain stops | Water drains back down on its own | Water stays put until the line is cleared |
| History | Happens only in big storms | Slow drains and gurgling for weeks beforehand |
If several clues lean toward the street, report it to 311 as well as calling a contractor.
The first hour
Safe steps while sewage is backing into a Somerville basement
Your priorities are to stop feeding the backup, protect people, and keep electricity away from water.
- Ask every household upstairs to stop running waterGo upstairs or text the other households. In a triple-decker, three kitchens and three bathrooms drain into the same building drain, and every flush ends up on your basement floor.
- Shut the main if a supply line is also leakingThe main valve is usually near the water meter where the service enters the basement. Closing it also stops anyone from absent-mindedly running water.
- Do not walk through sewage near the panel or appliancesIf water is near outlets, a furnace, a water heater or a washer, stay out of it. Cut power at the panel only if you can reach it while standing somewhere dry.
- Ventilate and limit time down thereSewer gas can contain hydrogen sulfide [4]. Open a window if you can do so safely, and do not linger in a basement that smells strongly of rotten eggs.
- Leave drain chemicals and the garden hose aloneChemicals will not move a main line blockage, and running a hose into the drain just adds more water to a pipe that is already full.
- Photograph the water and what it touchedPictures help when you talk with the contractor, the city or your insurer later. Take them from the stairs, not from the middle of the floor.
City side
Should I call Somerville 311 about a sewer backup?
The city's Water and Sewer Department maintains public sewers and pump stations, cleans catch basins, and responds to emergency calls for sewer backups [3]. If you suspect the street sewer, call 311 from inside Somerville; the department page lists the number to use from outside. Report the address, the time it started, and whether neighbors have the same problem.
Where city responsibility ends and yours begins along the lateral is something to ask the Water and Sewer Department about for your particular street, rather than assume. If the city finds its main clear, the blockage is likely on private pipe, and that is when a drain contractor's cable or jetter is the right tool. Somerville's long-term overflow plan includes sewer separation in parts of the city, such as Ten Hills and Winter Hill, intended to reduce how often combined sewers overflow [1].
Main line work
What urgent sewer line cleaning in a Somerville basement looks like
- 1
Confirming the backup is house-side
The contractor asks about rain, neighbors and fixture use, and may look at whether water drains back when no one is running anything.
- 2
Opening the main cleanout under control
A full building drain is under pressure. The cap is loosened gradually with buckets and a wet vacuum ready so the release does not spread sewage further.
- 3
Running a sectional machine toward the street
A heavy cable with a cutting head is fed through the building drain and out along the lateral until the line breaks through and the water drops.
- 4
Reading what came back on the cutter
Fine roots point to clay joints; grease points to kitchens; wipes point to bathrooms; heavy rust flakes point to aging cast iron.
- 5
Flushing the line and scheduling a closer look
Fixtures are run to confirm flow. If roots or a belly are suspected, a camera inspection is suggested once the basement is safe. Pipe repair or a backwater valve is permit work for a licensed plumber [5].
Afterward
After the Somerville sewer backup: cleanup, follow-up and prevention
Once the line is flowing, the floor still needs attention. Sewage-soaked cardboard, carpet and drywall generally should go. Hard surfaces need cleaning and disinfecting, with gloves and boots on. If the backup was significant, a water damage firm may be worth involving.
Then come back to cause. If roots were found, read about tree roots in clay sewer laterals. If the problem keeps coming back, the scheduled main sewer line cleaning page and the sewer line inspection page explain longer-term options. If the floor drain was the only symptom, see the guide on a basement floor drain backing up.
Sewage questions
Somerville basement sewage backup questions answered plainly
How can I tell if the city sewer or my own pipe caused the backup?
If it happens during heavy rain and neighbors have it too, the city sewer is a likely cause; if it happens when you run water on a dry day, suspect your own line. A blocked private lateral backs up whenever water is used in the building. Report street-wide problems to 311, and call a contractor about your own line. The basement floor drain guide explains the signs in more detail.
Is it safe to clean up basement sewage myself?
Small amounts can be cleaned with care, but sewage carries bacteria, so wear gloves, boots and eye protection and keep children and pets away. Do not touch electrical equipment standing in water, and turn off power to the area only if you can do so safely. Throw away porous items that soaked up sewage. For large or repeated backups, a professional cleanup company may be the safer choice.
Will a backwater valve stop storm backups in Somerville?
A properly installed backwater valve can reduce storm backups by closing when sewer water flows the wrong way. It must be the right type, placed correctly, and maintained, and fitting one is permit work for a licensed plumber in Massachusetts. It does not help with a blockage in your own line. Ask the contractor whether your building's layout suits one after the line has been cleared.
What does urgent sewer line cleaning in a basement usually involve?
The contractor opens the cleanout or another access point, runs a cable machine toward the street, and may follow with a camera. Once the blockage clears, water in the floor drain should drop quickly. If roots, grease or a broken section caused it, they may recommend main sewer line cleaning on a schedule or a sewer line inspection to look at repairs.
Who can clear a backed-up main sewer line in Somerville today?
A local drain contractor with main-line equipment can, and this number links you with one so you can confirm emergency availability. Nobody can promise an arrival time in advance. Tell them there is sewage in the basement, where the cleanout is, and whether it is raining. If the city main is the cause, they will advise you to report it to 311.
Can I run the washing machine after the sewer line is cleared?
Usually yes, once the contractor confirms the line is flowing, but go easy at first and watch the floor drain. Run a small load and check that nothing rises. If the clog was caused by roots or grease, it may come back, so ask whether a camera check is worthwhile. The tree roots guide explains why lateral clogs often return.
What other urgent drain help can I get for a basement backup?
You can also ask about urgent jetting, floor drain clearing and a camera look at the line. See emergency hydro jetting for heavy grease or roots, and emergency drain cleaning for help sorting out which drain failed. The complete list of drain work is on the services page, and the contractor you are connected with confirms what they offer.
