If you smell sewer gas coming from a floor drain, the cause can be a dry trap, a recent plumbing change, pressure swings, or something specific to the basement layout. Use the short article descriptions below to find the scenario that matches your situation and follow the linked guide for step-by-step checks and fixes.
Related topics on floor drains and main lines: Floor Drains, Basement & Main Lines
After repairs, remodels, and installations
This section covers smells that start after someone worked on your plumbing or when new equipment was put in. Those projects can let sewer gas past seals or leave traps dry.
- Smell after plumbing repair
A recent repair can leave traps open or push debris into vents; this article walks through checks a homeowner can do first. - Smell after remodel
Remodeling can interrupt vents, move drain lines, or leave construction debris—this guide helps pinpoint common remodel-related causes. - Smell after filter install
Installing a water filter or softener sometimes requires shutting lines or changing flow; read how to verify seals and traps after installation. - Smell after water heater install
New water heaters involve plumbing work and drained lines; this article explains what to check when odors appear after the install. - Smell after drain cleaning
Professional or DIY drain cleaning can dislodge biofilm and let gases escape temporarily—find tips to flush and reseal traps safely.
After outages, pressure changes, or being away
Loss of water, pressure shifts, or long absences can let traps dry or change flow in main lines. This section focuses on those intermittent events.
- Smell after city outage
When municipal service is interrupted, water in traps can siphon away or vents can change pressure; this piece shows how to restore proper traps and vents. - Smell after pressure change
Sudden pressure swings can open trap seals or push odors through vents—learn how to identify pressure-related causes and simple fixes. - Smell after smart shutoff trip
A smart shutoff can close lines and leave traps dry; this short guide explains which drains to refill and how to check valves. - Smell after turning water back on
Restoring water after a shutoff can release trapped gases or move debris—this article lists quick steps to clear odors after service resumes. - Smell after vacation
Long absences often let traps dry and odors build; the guide shows which drains to add water to and how to prevent recurrence. - Smell after winterization
Winterizing plumbing can remove water from traps—this piece explains how to recondition traps safely when you return pipes to service.
Basement and floor-drain specific situations
Basements and laundry areas have unique drain layouts and floor drains that are prone to dry traps and backflow. These articles focus on problems tied to below-grade drains.
- Sewer smell from basement drain
If the odor is centered at a floor drain, this article lists the most likely causes and step-by-step checks for basement floor drains. - Smell only in basement
When the smell is confined to the basement, the problem is often local vents, a dry trap, or a trap primer issue; this guide shows what to inspect. - Smell when washer drains
Washer discharge can push odors through a dry or poorly trapped floor drain—read how to adjust connections and test the trap seal.
Timing and pattern clues
When the smell appears—night, winter, or on and off—gives important clues about cause and severity. These short reads help interpret patterns.
- Odor only at night
Nighttime odors often point to temperature inversion or pressure changes in vents; this article outlines diagnostic steps to narrow the cause. - Smell comes and goes
Intermittent smells suggest a pressure or flow issue rather than a constant leak; learn how to spot cyclic triggers and test vents. - Smell worse in winter
Cold weather can affect venting and trap evaporation; this guide describes why winters worsen odors and what preventive steps help.
All Articles in This Cluster
- Sewer smell from basement drain
- Odor only at night
- Smell after plumbing repair
- Smell after city outage
- Smell after winterization
- Smell after remodel
- Smell after pressure change
- Smell when washer drains
- Smell after filter install
- Smell after smart shutoff trip
- Smell after turning water back on
- Smell after vacation
- Smell after water heater install
- Smell worse in winter
- Smell comes and goes
- Smell only in basement
- Smell after drain cleaning