Sewage backups and drain overflows in Assonet are among the most hazardous water damage events a property can experience. Category 3 black water — raw sewage, backed-up drain lines, toilet overflows — carries bacteria, viruses, and pathogens at concentrations that make any contact a serious health risk. COS Water Damage Restoration's Assonet sewage cleanup team is trained, equipped, and certified under IICRC S520 protocols for Category 3 biohazard remediation — from containment through full restoration.
📞 Call +1-844-499-0972 — Assonet Sewage ResponseSewage cleanup in Assonet is not a standard water damage job. The contamination levels, regulated disposal requirements, containment procedures, and sanitization standards that apply to Category 3 events are fundamentally different — and using a company without specific Category 3 training and equipment leaves your property and your household at risk.
IICRC certification is the standard that defines whether a sewage cleanup was done correctly. Our Assonet team is certified. The difference is measurable.
Proper disposal is a regulatory requirement, not a premium upgrade. It's standard on every Assonet job.
One application of sanitizer after a sewage event is not sufficient. Our protocol uses multiple applications with documented dwell times.
Our Assonet claim coordinators handle the insurance piece. We can coordinate clearance testing when it's required.
Here's what our certified Assonet Sewage Cleanup crew handles on every job.
The first action our Assonet sewage crew takes on any Category 3 event is establishing negative-pressure containment — critical plastic sheeting barriers that prevent sewage contamination from spreading into unaffected areas of the property through airborne particles, foot traffic, and air circulation. Containment also controls odor migration within the property while remediation is underway. Simultaneously, we identify and coordinate the correction of the blockage or failure that caused the backup — whether that's a main line obstruction, a failed cleanout, or a sump failure — so that remediation isn't interrupted by a secondary event.
No material gets dried in place unless it passes decontamination protocol first.
Sanitization happens before drying equipment is staged. This sequence matters.
Odor neutralization is a final treatment step, not a product sprayed at the end to cover incomplete remediation.
Most MA homeowner's policies cover sewage backup events under a backup coverage rider. Our Assonet claim coordinators are familiar with the specific documentation that backup claims require — including the distinction between backup events (covered) and sewer line failures (may require separate coverage) — and build your claim file from the first day to match what your carrier's adjuster will look for. We file the claim, coordinate the adjuster visit, and follow the settlement through. You focus on your household; we handle the insurance.
One company from sewage backup to finished reconstruction. No coordination gap, no separate contractor handoff.


Sewage events require immediate evacuation of affected areas. Our dispatcher will confirm this on the call.
Containment before contact. Source identified and addressed before cleanup proceeds.
After initial containment and source control, our Assonet project manager assesses the full Category 3 contamination extent, identifies all materials requiring removal, and prepares a written Xactimate-based scope covering extraction, material removal, sanitization, structural drying, and reconstruction. You review the scope and the cost before any material removal or treatment begins. If insurance is involved, the claim is filed the same day.
Extraction, material removal, multi-phase sanitization, structural drying, and reconstruction proceed under your approved scope. Daily progress updates keep you informed. Clearance testing is coordinated where required or requested. Final sign-off at a walkthrough with your project manager. Written satisfaction guarantee on every Assonet job.



"We have a young child and a dog and the moment the sewage smell hit I knew this was something I couldn't handle myself. COS Water Damage Restoration's Assonet team was there in under 60 minutes, contained the area so our family could stay in the upper floors, and handled every part of the cleanup in a way I trusted. The clearance testing they coordinated at the end gave me documented proof that the remediation was complete."
"The thing that stood out with COS Water Damage Restoration's Assonet sewage cleanup team was the containment setup — I've seen other companies skip it or do it loosely, and you can tell they don't understand why it matters. This team had proper negative-pressure containment up before they extracted a gallon of water. The two-phase sanitization after material removal, the hydroxyl generator running during drying, the final surface swab coordination — this was a Category 3 remediation done to the actual standard, not a watered-down version of it."
"I've used general contractors for water damage before with mixed results. After calling COS Water Damage Restoration for a sewage event in Assonet, I understand the difference between a certified Category 3 remediation team and a general restoration company that 'also does sewage.' The protocols aren't comparable."
COS Water Damage Restoration's certified Category 3 sewage cleanup team serves Assonet and surrounding communities throughout MA. Call +1-844-499-0972 to confirm same-day service at your address.
Don't let an uncertified company handle a Category 3 sewage event in your Assonet property. The health risk from incomplete remediation is real. Call +1-844-499-0972 — our certified Assonet team handles it correctly.
📞 Call +1-844-499-0972 — Assonet Sewage Response24/7 Response · IICRC S520 Certified · Category 3 Protocols · Assonet, MA