Sewage backups and drain overflows in San Marcos 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 San Marcos 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 — San Marcos Sewage ResponseThe four factors that make our San Marcos 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 San Marcos team is certified. The difference is measurable.
Proper disposal is a regulatory requirement, not a premium upgrade. It's standard on every San Marcos job.
One application of sanitizer after a sewage event is not sufficient. Our protocol uses multiple applications with documented dwell times.
Our San Marcos claim coordinators handle the insurance piece. We can coordinate clearance testing when it's required.
COS Water Damage Restoration handles the complete scope of Sewage Cleanup in San Marcos — from containment and extraction through material removal, sanitization, structural drying, and rebuild. Category 3 protocols, start to finish.
Containment is established before extraction begins. This is non-negotiable on every San Marcos sewage job.
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.
Our San Marcos claim coordinators have processed Category 3 claims across CA carriers. We know what gets approved on first submission.
One company from sewage backup to finished reconstruction. No coordination gap, no separate contractor handoff.


Call +1-844-499-0972 and a live San Marcos dispatcher answers — not a recording. Describe the situation; our dispatcher confirms the sewage backup details, dispatches the nearest Category 3-equipped crew, and confirms estimated arrival. Evacuate the affected area and prevent household members and pets from entering while we're en route.
Containment before contact. Source identified and addressed before cleanup proceeds.
No extraction, no material removal before the written scope is reviewed and approved by you.
From sewage event to finished property — documented, guaranteed, and handled by one company.



"When our basement drain backed up in San Marcos, 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."
"Three years later, no odor, no mold, no recurring issues. COS Water Damage Restoration did the San Marcos sewage cleanup right the first time. I'm telling every neighbor I know to call them first."
"I've used general contractors for water damage before with mixed results. After calling COS Water Damage Restoration for a sewage event in San Marcos, 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 San Marcos and surrounding communities throughout CA. 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 San Marcos Category 3 team responds fast, contains the event, and remediates to the standard that protects your household.
📞 Call +1-844-499-0972 — San Marcos Sewage Response24/7 Response · IICRC S520 Certified · Category 3 Protocols · San Marcos, CA