Sewage backups and drain overflows in Sullivan 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 Sullivan 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 — Sullivan Sewage ResponseThe four factors that make our Sullivan Sewage Cleanup service different from a general water damage company handling a sewage call.
IICRC certification is the standard that defines whether a sewage cleanup was done correctly. Our Sullivan team is certified. The difference is measurable.
Sewage-contaminated materials removed from Sullivan properties — carpet, pad, drywall, insulation, and any porous material that absorbed Category 3 water — require regulated waste handling and disposal. Our Sullivan crew bags, labels, and disposes of all contaminated material to applicable NH regulatory requirements. No dumping in standard refuse. No leaving contaminated materials in dumpsters that aren't rated for biohazard waste.
One application of sanitizer after a sewage event is not sufficient. Our protocol uses multiple applications with documented dwell times.
Sewage cleanup claims in Sullivan typically proceed under homeowner's policy coverage for drain backup and water damage. Our Sullivan coordinators are experienced with backup coverage riders and know how to document Category 3 events for claim approval. For commercial properties or clients requiring clearance testing, we coordinate third-party air quality and surface sampling after remediation to provide a written clearance certificate before reconstruction begins.
COS Water Damage Restoration handles the complete scope of Sewage Cleanup in Sullivan — from containment and extraction through material removal, sanitization, structural drying, and rebuild. Category 3 protocols, start to finish.
The first action our Sullivan 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.
Extracting Category 3 sewage water from a Sullivan property requires specific PPE — full protective suits, respirators rated for biological hazard, and disposable boots — for every technician in the contamination zone. We use dedicated contaminated-water extraction equipment that is not shared with standard water damage jobs and is properly sanitized between uses. After extraction, all materials that contacted Category 3 water and cannot be decontaminated to a safe standard — carpet, pad, standard drywall, fiberglass insulation, and any non-cleanable surface materials — are removed as regulated waste, bagged in approved containers, and disposed of under NH biohazard material regulations.
Sanitization happens before drying equipment is staged. This sequence matters.
Category 3 sewage events leave odor-causing compounds embedded in structural materials, in the air space above the affected area, and — in HVAC systems — potentially distributed throughout the property. Our Sullivan team uses hydroxyl generator technology and botanical-based counteractant treatments to neutralize sewage odor compounds in the air and on surfaces, not mask them. For properties where HVAC ductwork may have been exposed to Category 3 contamination, duct isolation and decontamination is included in our scope evaluation.
Our Sullivan claim coordinators have processed Category 3 claims across NH carriers. We know what gets approved on first submission.
After Category 3 remediation is confirmed complete by instrument readings and — where required — by third-party clearance testing, our licensed Sullivan reconstruction team rebuilds your property: new drywall, fresh insulation, flooring, paint, trim, and any affected cabinetry or millwork. All reconstruction is performed to the same documentation standard as the remediation phase, providing a complete recovery record from sewage event to finished property that your insurance carrier and any future property transaction will find clear and complete.


Sewage events require immediate evacuation of affected areas. Our dispatcher will confirm this on the call.
Our Sullivan crew arrives in full Category 3 PPE with containment materials, dedicated contaminated-water extraction equipment, and sanitization products. Containment is established before extraction begins — no exceptions. After containment, we identify the source of the backup and coordinate correction if needed before the cleanup scope is assessed.
After initial containment and source control, our Sullivan 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 Sullivan job.



"When our basement drain backed up in Sullivan, I didn't realize I was dealing with a sewage event until the smell made it obvious. COS Water Damage Restoration arrived within the hour, set up containment before anyone entered the space, and explained the Category 3 protocols clearly — including why certain materials had to be removed and couldn't just be dried in place. They disposed of everything properly, treated all surfaces with a sanitization protocol I could actually track through each step, and filed the insurance claim the same day. The reconstruction brought the basement back completely. I feel good about the space now, and that was not a given after the event."
"The thing that stood out with COS Water Damage Restoration's Sullivan 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 Sullivan, 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 Sullivan and surrounding communities throughout NH. Call +1-844-499-0972 to confirm same-day service at your address.
Sewage contamination requires certified remediation — not a general cleanup crew. Call +1-844-499-0972 and our Sullivan Category 3 team responds fast, contains the event, and remediates to the standard that protects your household.
📞 Call +1-844-499-0972 — Sullivan Sewage Response24/7 Response · IICRC S520 Certified · Category 3 Protocols · Sullivan, NH