Quick Answer:
If several fixtures back up while testing new sinks after a remodel, stop using the new fixtures immediately. Shut off the water to the new fixtures, remove and inspect accessible traps and the nearest cleanout for plaster, grout, or packing tape, and avoid tools or techniques that might push debris farther into the branch. If traps and the nearby cleanout are clear, ask the contractor for a short camera inspection before you run power snakes or the disposal for long periods.
Why This Happens
Remodel work creates small bits of material—plaster dust, grout fragments, adhesive, packing tape and similar debris—that can lodge in traps or the branch drain serving the work area. When a new fixture is run for the first time, that water flow can dislodge trapped material and send it into other fixtures on the same branch. If multiple fixtures clog at once it can feel like a sudden system failure; this is often a local branch problem rather than the main line. A quick contractor camera check can confirm whether the blockage is in the immediate branch or deeper in the system. If you want more reading on related issues, see the article on Multiple drains clog suddenly.
Step-by-Step What to Do
Step 1 — Stop and shut off water
- Turn off the water supply to the new fixtures right away to avoid pushing more debris through the drains.
- If the fixture has a local shutoff valve, use that first; otherwise shut off the house valve for that branch.
Step 2 — Check the trap and nearest cleanout
- Locate the P-trap under the new sink and the accessible cleanout nearest the remodel area.
- Open the cleanout (if you can) and look for plaster, grout, tape or chunks of material. These often collect near the entrance to the branch.
Step 3 — Remove and inspect P-traps
- Place a bucket under the trap, loosen the slip nuts, and remove the P-trap to inspect for trapped debris.
- Clean it out thoroughly and check the trap inlet for material that might block flow further into the branch.
Step 4 — If traps and accessible cleanouts are clear, get a short camera inspection
- Ask the contractor for a short camera inspection of the branch serving the remodeled fixtures. A quick video will show whether debris is lodged inside the branch or further downstream.
- Keep the inspection focused and brief to save time and cost—often a 10–20 foot run into the branch is enough to locate the blockage.
Step 5 — Use the right clearing method
- Avoid motorized snakes that run long distances into the main line for this first pass; they can push debris deeper.
- Use a manual auger into the immediate branch only if you are comfortable doing so. A short hand auger can retrieve or dislodge debris without driving it farther into the system.
- If the camera shows material in the branch or you can’t retrieve debris by hand, stop and call a professional.
What Not to Do
- Do not run the kitchen garbage disposal continuously to try to clear remodel debris—this can grind materials and push them into the main or create a worse clog.
- Do not use high-speed motorized snakes that extend far into the main branch if you suspect loose construction debris; they can push material deeper and make the problem harder to locate.
- Do not assume the contractor’s cleanup removed everything—call a pro when debris is suspected inside the main branch or after contractor work if simple trap cleaning doesn’t fix it.
When to Call a Professional
- Call a plumber if cleaning traps and the nearest cleanout doesn’t restore flow.
- Call if a camera inspection shows debris lodged inside the branch or main line—professionals have tools and techniques to remove it without pushing it deeper.
- Call if there are multiple affected fixtures throughout the house or recurring backups after briefly clearing the branch; those signs can indicate a problem beyond the immediate remodel area.
Safety Notes
- Wear gloves and eye protection when removing traps or opening cleanouts—remodel debris and sewage can both be present.
- Have a bucket and rags ready; expect some water and debris when you open traps or cleanouts.
- If you are unsure how to use an auger or access a cleanout safely, stop and call a professional to avoid injury or damage.
Common Homeowner Questions
- How quickly should I shut the water off?
Immediately—stopping flow limits how far debris can travel. - Will the contractor fix this if it’s their work?
Often yes; ask them to run a camera inspection and clean the branch. If they refuse, document the problem and consider calling a plumber. - Is it safe to use enzymatic cleaners after a remodel clog?
They won’t clear construction debris. Only use cleaners for organic buildup after the solid debris is removed.
More in this topic
For more related fixes and similar symptoms, see Multiple Fixtures Backing Up Together.