Sketch of common septic system component setbacks and clearances. Problems with a Neighbor's Septic System

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Trouble from neighbor's septic system:

This article offers advice for investigating, diagnosing, and resolving odor, seepage, or well contamination problems that appear to originate on a neighbor's property.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Advice for Investigating Septic Odors, Seepage, Failures, on Neighboring Lands

Photograph of melting snow indicating septic tank location

Hi, My neighbor has a septic tank in the front of their house, the house is about 30 years old. I can smell her septic on certain days but my concern is that it is very close to the property line and their property is about 8 feet higher in elevation and I think the waste is leaching into our yard.

Originally the yards were pretty level, but we cut away the banking to make a driveway. How can I tell if that waste is in the soil around our driveway.

Oh yeah, the banking doesn't freeze there in the winter.  Thanks, C

Check with your Neighbors

In general, septic effluent must be disposed of on the property from which it originates.

It’s always best to ask a neighbor to consider and address a problem before calling the authorities, but if a neighbor is unwilling or perhaps unable to act, the second step of involving the health department may be necessary.

In my experience, when an owner’s property was sending raw septic effluent onto a neighbor’s property and the offender refused to address the matter, the health department would get involved and require action.

Whenever there seems to be a problem that begins with a neighbor's property, we advise a prompt, courteous inquiry with the neighbor involved. Explain your concerns, invite their assistance, give the neighbor an opportunity to respond. Usually that approach will lead to satisfaction for everyone.

If you have the bad luck to encounter a neighbor who is unable or unwilling to assure that their septic system is not contaminating a neighbor, other steps may be necessary.

Check the distances between the neighboring septic system and property boundaries, wells, etc

Sniffing out septic odors at a farmhousePerhaps start your research by looking at CLEARANCE DISTANCES, SEPTIC SYSTEM and then review the distances between the neighboring septic system and your property lines and anyone's well with your local health department.

Clearance distances from wells, property lines, streams, etc. must all be respected.

Investigate the source of septic odors

Sniffing out odors on your own property can be a challenge, and you should stay off of a neighbor's land unless you're invited there.

Odors may mean the neighbor’s system is in failure, or that their plumbing and venting are improperly installed, or (less likely) there could be another odor source. In my experience, most health departments will require action of septic effluent is actually entering a neighbor’s property, but won’t require action on odors.

So if your neighbor’s system is producing wet spots or wet areas on your land, they will most likely be required to fix that. Here is our article on diagnosing septic odors:

Investigate the source of wet areas that might or might not be due to someone's septic system failure

If there are wet areas that may be due to a septic problem

Septic failure by a pool

In this photo, excavation for an above ground pool disclosed sewage effluent flowing to the surface at an adjoining property.

If there are wet areas produced on your land, or for that matter, on the neighbor’s nearby land, their septic system may be in failure and needs repair for health reasons as well as functional reasons.

Here is a list of septic system failure criteria:

When effluent appears, the health department may use a septic dye to attempt to assure that the effluent is from a septic system and not another groundwater source.

I find that septic dye usually but not always appears in less than a day in the wet areas when the septic has failed.

At times the septic is in failure but the dye doesn't show up – because of dilution by other groundwater or use of bleach by an owner

. An explanation of how septic dye may not appear even though a septic has failed is at

If there are no wet areas but you still suspect a septic problem

Septic failure evidence

This photo shows an uphill neighboring septic field whose effluent flowed below ground into the drive drainage system of the property in the foreground of the picture. This photo shows septic dye appearing in the area drain basin in the driveway.

If there are no wet areas developing but the ground shows evidence of nearby effluent passage such as odors or warmth in winter, it may be expected that soon enough effluent will be appearing and the issue will become unambiguous – repair will be required.

Pay special attention to suspect areas during wet weather.

If there are no wet areas being produced on your land then effluent is not appearing at the ground surface, that is, if there is no visual evidence of septic failure, and absent a clearance distance issue which I introduced above,I'm not sure your health department would consider the neighbor to be in violation of health codes.

Soil testing for evidence of septic failure

Testing a soil for coliform bacteria or e coli bacteria to indicate that it’s contaminated with sewage effluent can be performed by a local water testing lab.

I’d call the lab to ask them the procedure they want you to use to test a soil sample rather than a water or groundwater sample, and I’d ask what standards of comparison are used. (And I ask that you share that information with me.)


Continue reading at CLEARANCE DISTANCES, SEPTIC SYSTEM or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see NEIGHBOURING SEPTIC SYSTEM FAQs - questions & answers posted originally at this article.

Also see WELL CLEARANCE DISTANCES for required distances between wells and septic systems and other site features.

Or see these

Articles on Site Plumbing or Mechanical System Clearances

Suggested citation for this web page

NEIGHBORING SEPTIC SYSTEM PROBLEMS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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