Warning Signs and Troubleshooting
Septic failures rarely happen without warning. These are the signals worth acting on.
25 questions in this section
- What are the classic warning signs of septic failure?
- My drains are slow throughout the house. Is that the septic?
- Why do my drains gurgle?
- I have a wet, spongy area over my drain field. What does it mean?
- The grass over my drain field is greener than the rest of the lawn. Is that bad?
- I smell sewage in my yard. What should I check?
- I smell sewage inside the house. What causes that?
- Sewage backed up into my basement. What do I do first?
- Why does my system back up only when it rains?
- Can my system fail from too much water rather than too much waste?
- What causes drain field failure?
- How do I know if it is the tank or the field?
- Can tree roots damage my system?
- How far should trees be from my septic system?
- My toilet flushes fine but the tub drains slowly. What does that mean?
- Can a septic system explode or be a fire risk?
- Is standing water near my system always a septic problem?
- My system is old but seems to work. Should I worry?
- What shortens a septic system's life the most?
- Can I repair just part of my drain field?
- My pump keeps running or will not shut off. What is wrong?
- What if my system freezes in winter?
- Should I try to fix a septic problem myself?
- How urgent is a surfacing failure?
- Can a failing septic system contaminate my well?
What are the classic warning signs of septic failure?
Sluggish drainage inside the home, plumbing backups, gurgling in pipes and drains, outdoor odours, mushy or soggy ground over the septic area, and a heaved or collapsed sewer line.
My drains are slow throughout the house. Is that the septic?
If it is one fixture, it is probably a local clog. If every drain in the house is slow, suspect the septic system - most often a full tank, a clogged effluent filter or a failing field.
Why do my drains gurgle?
Gurgling means air is being displaced somewhere it should not be. It commonly signals a partially blocked line, a full tank or a blocked plumbing vent.
I have a wet, spongy area over my drain field. What does it mean?
Effluent is surfacing because the soil cannot accept it. That is a health hazard - the water on the surface is untreated sewage. Keep people and pets away and call a licensed installer immediately.
The grass over my drain field is greener than the rest of the lawn. Is that bad?
A slightly greener strip is not unusual. Dramatically lush, fast-growing grass over the field, especially with soft ground, indicates effluent is reaching the surface. Have it looked at.
I smell sewage in my yard. What should I check?
The area over the tank and field for wet spots, the tank lids for damage, and the roof vent for blockage. A persistent outdoor odour is not normal and warrants a service call.
I smell sewage inside the house. What causes that?
Usually a dry P-trap in a seldom-used fixture, a failed wax seal at a toilet, or a blocked plumbing vent. If those are ruled out, it may be backflow from the system.
Sewage backed up into my basement. What do I do first?
Stop using water immediately. Keep people and pets away from the affected area, do not walk through it, and call a licensed installer or septic service. Sewage backup is a biological hazard and needs professional cleanup.
Why does my system back up only when it rains?
Because the soil around the field is already saturated, or because surface water is being directed into the system. Check that roof drains, foundation drains and sump discharge are routed well away from the field, and look at whether an interceptor drain is needed upslope.
Can my system fail from too much water rather than too much waste?
Yes, and it commonly does. Excess water - from leaks, storm water, a running toilet or heavy simultaneous use - flushes solids into the field and prevents the soil from treating anything properly.
What causes drain field failure?
Overloading with water, solids escaping from an unpumped tank, root intrusion, soil compaction from vehicles, poor original siting, an unlevel distribution box, and simple age.
How do I know if it is the tank or the field?
A tank problem often clears temporarily after pumping. If pumping fixes it for a week and the symptoms return, the field is the problem. A licensed installer can confirm with an inspection.
Can tree roots damage my system?
Yes. Roots seek the water and nutrients in your field and can enter and block distribution lines, and they can crack tanks and pipes. Willow, poplar and maple are especially aggressive.
How far should trees be from my septic system?
A common rule of thumb is at least as far as the tree's expected mature height. Only grass should be planted over and near the system.
My toilet flushes fine but the tub drains slowly. What does that mean?
That pattern usually points to a partial blockage in a branch line rather than a system-wide problem, because the tub sits lower. Still worth ruling out the septic if other symptoms appear.
Can a septic system explode or be a fire risk?
Methane and hydrogen sulphide accumulate in tanks and are both toxic and flammable. Never introduce a flame or spark near an open tank, and never enter one.
Is standing water near my system always a septic problem?
Not always - it could be poor grading or a high water table. But standing water over the tank or field, especially with odour, should be treated as a septic issue until proven otherwise.
My system is old but seems to work. Should I worry?
Age alone is not failure, but plan ahead. Most systems last 15 to 40 years, and drain fields commonly 20 to 30 years with good maintenance. Knowing your system's age lets you budget rather than react.
What shortens a septic system's life the most?
Skipping pumping, driving on the field, connecting storm water, using a garbage grinder heavily, and chronic water overloading. Neglected systems can fail in as little as 10 to 15 years.
Can I repair just part of my drain field?
Sometimes a portion can be replaced or a distribution problem corrected. In New Brunswick, any excavation within the limits of the disposal field - including apron or taper - requires an approval first.
My pump keeps running or will not shut off. What is wrong?
Usually a stuck float switch, a failed check valve letting effluent run back, or a leak somewhere in the system. Turn it off at the breaker if it is cycling continuously and call for service.
What if my system freezes in winter?
Stop adding water, do not add antifreeze or salt, and call a septic professional with thawing equipment. Never use an open flame. Once thawed, address the cause - usually insufficient cover, compacted snow or low usage.
Should I try to fix a septic problem myself?
No. Beyond cleaning the effluent filter and reducing water use, septic repairs in New Brunswick legally require a licensed installer and an approval. The hazards are also real: confined spaces, toxic gas and pathogens.
How urgent is a surfacing failure?
Very. Untreated sewage on the surface can contaminate wells and surface water and is a direct health risk to your family and neighbours. Report it and get it repaired promptly.
Can a failing septic system contaminate my well?
Yes, which is exactly why the separation distances exist. If you suspect a failure, test your well water for total coliform and E. coli, and use bottled water until results come back.
Have a question about your own property? General answers only go so far — your soil, slope, water table and setbacks are specific to your lot. Call (506) 233-6272 or send us the details.
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