Sample of a property tax billHow Do We Find Out if a Building is Actually Connected to a Sewer System - or to a Septic Tank?

  • Clues Indicating a Building is Connected to Sewer - CONTENTS: What clues can confirm that a particular home or building has been connected to the public sewer main? Step by step procedures to find out if a building is connected to a septic tank or private onsite waste disposal system. What to do if you are buying a home and don't know if it is connected to a septic tank or a sewer line
  • SEPTIC VIDEOS show how to walk the site for possible septic tank & drainfield locations
  • POST a QUESTION or READ FAQs about how to figure out if a home is connected to public sewer or private septic

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Septic or sewer connection determining by clues:

\This article what clues can confirm that a building has actually been connected to a public sewer, or on the contrary, that it is connected to a private septic tank system. In the previous section of this article we explained how to determine whether or not a public sewer is available at a property.

Here we continue by discussing how to to find out if a particular building has actually been connected to an available sewer main. A reader asked, "How do I know if the house I am purchasing has a septic tank?" Even if a sewer is installed right in the street in front of a building, that building may never have been connected to the sewer line. Here are some clues that help sort out this question.

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Clues Indicating That a Building Has Been or Has Not Been Connected to the Public Sewer

Storm drain connected to a sewer

No room for septic systems: If lots in the area are very small there may not be room for private septic systems to have been installed in the first place.

Usually we'll find that a public or a community sewer main has been provided and that the closely-spaced homes or cluster homes are connected to that system.

But be careful. In some communities we find that new cluster housing or town houses on a street are all connected to a municipal sewer line, but on the same street a number of older, pre-existing homes are all served by private septic systems.

Look at the size available on the individual lot surrounding the property you are investigating, and consider when that home or building was constructed.

Snow melt and depressions show the location of a septic drainfield

Depressions or cleanout access covers indicating that a septic tank is present (these may be present even if a building was later connected to a sewer, as we discuss further below). Depressions in the ground surface are caused by settlement of softer dirt following an excavation to install or service a septic system component.

These ground settlement marks may be small and round, just a couple of feet in diameter where someone dug up a septic tank cover, they may be larger and round or rectangular up to 6' x 10' if they mark a septic tank outline.

As our photo at left shows, multiple, long straight parallel depressions in the ground, especially in an area where there are no trees may indicate trenches of a septic drainfield. In winter in areas where snowfall occurs, snow-melt may also mark a septic tank or drainfield location.

Sample of a property tax bill

Tax deprtment records and tax bills
for a property often indicate a charge for connection to both public water and public sewer lines. But don't count on this data being correct.

Sometimes the tax department thinks the building is connected to a sewer and charges for it but in fact the building was never connected-up to that system.

Tax bills can be confusing to a new homeowner but you may find that the folks at the tax department will be friendly and happy to explain the bill to you. The tax department will show you if your tax bill includes an assessment for sewage services.

Building department records will usually record where sewer lines have been installed and which buildings have been connected to them. Be careful: on occasion we find that those records were mistaken, especially where newer sewer lines and older buildings are involved together.

Septic sketch
Drawings and plans:
papers describing the building's construction, and even sketches can tell if a septic tank or sewer connection is used for a building.

Often in older properties someone has sketched the distance to a septic tank right on the wall by the exit point of the main drain from the building.

Look there and look overhead among floor joists over a basement or crawl space for a paper that may have been placed there showing the drain destination.

Neighbors and Contractors: neighbors will have a vital interest in and are likely to know if buildings on the street are connected to a sewer system or to private septic tank systems.

Records of plumbers who worked on the building, or even local septic pumping companies may have records of what type of waste disposal system is at the property

Septic vs Sewer Connection Determination Articles


Continue reading at Guide for buildings Connected to a Public Sewer or select a topic from the More Reading links shown below.

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Clues Indicating a Building is Connected to Sewer at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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