How to Clean Up After a Toilet Overflows

A toilet overflow turns an ordinary morning into a cleanup job in seconds. Water spreads across the floor, slips under the baseboards, and heads for the sub floor.

How you clean it up depends on what is in the water. A tank of clean water and a bowl full of waste call for very different responses.

This guide covers stopping the flow, judging how contaminated the water is, cleaning up safely, and knowing when the job is too big for a mop and bucket.

Stop the Water First

Every second the toilet keeps running adds more water to the floor. Stop the flow before you think about cleanup.

1. Don’t flush again. American Standard warns against trying to clear a clog by flushing over and over.
2. Close the shutoff valve behind the toilet by turning it clockwise.
3. If the valve is stuck, lift the tank lid and pull up on the float so the tank stops refilling.
4. Press the flapper down to keep more water from flowing into the bowl.

Once the water stops, step back and figure out what you are dealing with.

If the same toilet keeps backing up, the cause may be in the fixture itself. It’s worth learning how to diagnose a toilet problem before the next overflow.

Is It Clean Water, Gray Water or Black Water?

Restoration pros sort water damage into three categories under the IICRC S500 water damage standard. The category decides whether a DIY cleanup is safe at all.

For a deeper look, see this guide to the three water categories that shape every restoration job.

Category 1 Clean Water

Water from a broken tank, or from a bowl with no waste or other contaminants in it, counts as clean water.

A tank that overflows because its fill valve sticks, before anyone has used the toilet, usually falls into this group.

Category 2 Gray Water

An overflow with urine but no feces is Category 2. The Massachusetts Department of Public Health lists it that way in its water damage quick reference.

Gray water doesn’t stay gray forever. Guidance based on the IICRC standard notes that gray water left untreated for more than 48 hours may change to Category 3.

Category 3 Black Water

Any overflow with feces is Category 3. So is any backflow that comes from beyond the toilet trap, no matter how clean it looks.

The IICRC describes Category 3 water as grossly contaminated and able to carry harmful agents. Here is more on the health risks of cleaning up black water yourself.

How to Clean Up a Small Toilet Overflow Safely

These steps fit a small overflow of clean or gray water that stayed on a tile or vinyl floor. If the water held feces or spread into other rooms, skip ahead to the next section.

1. Put on protective gear. The CDC recommends rubber boots, rubber gloves and goggles whenever sewage is involved.
2. Soak up standing water with old towels or a wet vacuum, and bag anything disposable.
3. Clean every hard surface with detergent and water first. The EPA notes that disinfectants such as bleach don’t work well until the dirt is cleaned away.
4. Sanitize hard, non-porous surfaces such as tile, porcelain and sinks.
5. Keep the room ventilated, and never mix bleach with ammonia or any other cleaner.
6. Wash the clothes you wore in hot water and detergent, then wash up with soap and water.

For step four, the CDC’s bleach guidance calls for 1 cup of bleach to 5 gallons of water on household surfaces after flooding.

What to Throw Away

The CDC advises throwing away anything you can’t clean or dry quickly, including carpet, padding, rugs and upholstered furniture.

A bath mat you can machine wash in hot water may be worth saving. A rug soaked through with toilet water usually isn’t.

The CDC also says to remove and discard drywall and insulation contaminated with sewage. For other items, use this guide on what to salvage and what to throw out after water damage.

Dry the Room Completely

Finish by drying the bathroom fully, including the area around and under the toilet base. The EPA warns that mold can grow on wood, drywall, carpet and furniture that stay wet for more than 24 hours.

When to Stop and Call a Professional

DIY cleanup has limits. Call a restoration company when any of these apply.

• The water contained feces, or it backed up from the drain line instead of overflowing from the bowl.
• Water reached carpet, drywall, cabinets or the ceiling of the room below.
• The overflow sat for a day or more before anyone found it.
• Water seeped under the toilet base or into the sub floor.
• Several drains in the house are backing up at the same time.

Water that drips through to a lower floor needs its own response, starting with what to do when your ceiling has water damage.

When the Problem Is Your Sewer Lateral

Drains that run slowly around the house can point to a blockage in the sewer lateral. That is the pipe carrying waste from your home to the sewer main.

The City of San Diego says the property owner is responsible for maintaining that lateral, from the property all the way to the sewer main connection.

Tree roots are one thing that can clog a lateral, and it helps to know how to keep tree roots out of your sewer line.

Hidden Damage and Insurance After an Overflow

Even a careful cleanup can miss water that slipped under the toilet base or the flooring. Watch for the warning signs of water damage in the bathroom, like loose tiles or a soft spot near the toilet.

Insurance treats an overflow and a sewer backup differently. A sudden overflow is generally the kind of sudden and accidental water damage a homeowners policy is meant to cover.

Sewer and drain backup is another matter. Many policies don’t cover it unless you added water backup coverage, so check your declarations page before you file.

For the bigger picture, see what California homeowners insurance covers for water damage.

Frequently Asked Questions

Is toilet overflow water dangerous?

It depends on what is in it. An overflow with urine only counts as gray water, while one with feces, or a backflow from the drain line, is black water that can carry harmful agents.

Can I use bleach to clean up after a toilet overflow?

Yes, on hard, non-porous surfaces after you clean them with detergent. The CDC’s mix for household surfaces is 1 cup of bleach to 5 gallons of water.

Do I need to replace the flooring after a toilet overflow?

Not always. Hard flooring that dried quickly is often fine, but water trapped under vinyl or tile, or soaked into the sub floor, usually needs professional drying or removal.

Clean Up Fast and Know Your Limits

A small, clean overflow is a manageable DIY job if you stop the water, clean before you disinfect, and dry everything. Anything involving waste, walls or ceilings is a different job.

Dealing with sewage or water in the walls? Pacific Flood Restoration provides sewage cleanup across San Diego County. Call (760) 815-3033, 24/7, or request a free estimate.