Quick Answer:
If you notice sewer smells during an outdoor walkaround, don’t assume the lateral is broken right away. Start by checking vents and traps inside, then smell-test around the cleanout, sewer cap, and low spots in the yard. If the odor points to the cleanout or a patch of yard, photograph it and keep the area sealed for the technician. A video camera inspection is the right next step to look for cracked pipes and root-invaded joints.
Why This Happens
Tree and shrub roots search for moisture and nutrients. Small cracks, loose joints, or degraded seals in a sewer lateral offer an attractive path. Roots can enter a joint, grow inside the pipe, and create a partial blockage that allows sewer gas to escape into the soil or air. Interior plumbing issues such as dried or siphoned traps, or blocked vent stacks, can also let sewer smells come into the house, so it’s important to rule those out before assuming outside root entry.
Wet soil after storms can speed root growth and increase the chance of intrusion; read more on how roots behave after a storm in Roots after heavy rain.
Step-by-Step What to Do
Step 1 — Check vent stacks and traps inside
- Inspect vents on the roof for obvious blockages (debris, bird nests). If a vent is blocked, it can cause slow air flow and trap siphoning.
- Run water in sinks, tubs, and floor drains to refill traps and note if the smell disappears. If a trap is dry or siphoned, the odor could be coming from inside the house, not the yard.
- If you’re not comfortable accessing the roof, proceed with outdoor checks and mention vent concerns to the technician.
Step 2 — Smell-test around the yard
- Walk the yard slowly after a still period (smells dissipate in wind). Stop at the sewer cleanout, the sewer cap, depressions, and soggy patches.
- Smell at different heights — ground level and standing up — to help locate the source.
- If the odor is strongest near the cleanout or a particular patch of lawn, treat that as a likely source and avoid disturbing the area.
Step 3 — Document and protect the spot
- If smell tracks to the cleanout or a specific yard patch, photograph the area from several angles and note the date and weather conditions.
- Keep the cleanout cap in place and avoid walking or digging on the affected patch. Covering or sealing the cleanout temporarily with its cap helps preserve evidence for the technician.
- Do not hose the area down or try to excavate — that can spread contamination and disturb roots.
Step 4 — Request a camera inspection focused on problem sections
- When contacting a plumber, ask specifically for a camera inspection of the lateral. Request that they focus on joints, cracked sections, and any signs of root intrusion.
- A camera can show whether roots have entered, whether the pipe is cracked, or whether a joint has separated. This guides repair choices: spot repairs, sectional replacement, or full lateral replacement.
- Keep your photos and notes handy to share with the technician.
What Not to Do
- Don’t spray air fresheners or mask odors which can hide the problem; masking the smell prevents accurate diagnosis.
- Avoid digging at the odor spot without a pro, which can disturb roots and spread contamination — call a pro when persistent sewer smells return or you see soggy ground near the cleanout.
- Don’t pour chemicals into the cleanout or drains trying to “kill roots.” Some chemicals can damage pipes, harm soil, and create hazardous fumes.
When to Call a Professional
- Call a licensed plumber if the smell returns after you refill traps and clear vents, or if the odor is clearly outside near the cleanout.
- Also call if you notice soggy ground, slow drains, backups, or sewage surfacing. These are signs of active leaks or major blockages that need professional equipment and safe handling.
- Ask for a camera inspection and a written estimate that explains recommended repairs and options.
Safety Notes
- Avoid direct contact with sewage or contaminated soil. Sewage can carry bacteria and viruses.
- Keep children and pets away from the affected area until a pro inspects it and confirms it’s safe.
- Don’t attempt confined-space entry (crawl spaces or trenches) or use heavy equipment yourself. Let professionals handle excavation and repairs to avoid injury and additional damage.
Common Homeowner Questions
- How can I tell if the smell is from my pipe or a neighbor’s? If the odor is strongest at your cleanout or your yard patch, it’s likely on your side. Document and photograph to show the technician.
- Will tree roots always mean a full pipe replacement? Not always. Small intrusions can sometimes be cleared and repaired; the camera inspection determines the extent.
- Can I prevent roots from coming back after repair? Replacement of damaged sections and proper joint seals limit re-entry; landscape choices and root barriers near the lateral help, but professional advice is best.
More in this topic
For more related fixes and similar symptoms, see Tree Root Intrusion Patterns.