Sewage backups and drain overflows in Chico 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 Chico 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 — Chico Sewage ResponseSewage cleanup in Chico 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.
COS Water Damage Restoration's Chico sewage cleanup crew operates under IICRC S520 standard — the industry's governing protocol for Category 3 contaminated water remediation. This covers the specific containment requirements, the PPE standards that protect our crew from pathogen exposure, the material removal requirements (what can be safely dried versus what must be removed and disposed of as a regulated waste stream), and the multi-application antimicrobial sanitization protocol that must be completed before any structural drying begins.
Proper disposal is a regulatory requirement, not a premium upgrade. It's standard on every Chico job.
One application of sanitizer after a sewage event is not sufficient. Our protocol uses multiple applications with documented dwell times.
Our Chico claim coordinators handle the insurance piece. We can coordinate clearance testing when it's required.
Here's what our certified Chico Sewage Cleanup crew handles on every job.
Containment is established before extraction begins. This is non-negotiable on every Chico sewage job.
No material gets dried in place unless it passes decontamination protocol first.
After material removal, every remaining structural surface — framing, subfloor sheathing, masonry, concrete, and any hard surface that contacted sewage water in your Chico property — receives a multi-phase sanitization treatment using EPA-registered, hospital-grade antimicrobial and antifungal agents. The sanitization sequence includes spray application, documented dwell time, surface contact, and at minimum one additional application after the first dwell cycle. This is not a one-spray process. The S520 protocol our Chico team follows is designed to address the pathogen load that Category 3 water deposits on structural surfaces.
Odor neutralization is a final treatment step, not a product sprayed at the end to cover incomplete remediation.
Our Chico claim coordinators have processed Category 3 claims across WA 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 Chico 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.


Call +1-844-499-0972 and a live Chico 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.
Our Chico 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 Chico 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.
From sewage event to finished property — documented, guaranteed, and handled by one company.



"When our basement drain backed up in Chico, 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 Chico 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 Chico, 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 Chico and surrounding communities throughout WA. 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 Chico property. The health risk from incomplete remediation is real. Call +1-844-499-0972 — our certified Chico team handles it correctly.
📞 Call +1-844-499-0972 — Chico Sewage Response24/7 Response · IICRC S520 Certified · Category 3 Protocols · Chico, WA