Is your home at risk?
Here's how to determine if you are at risk of a sewer backup.
Your home is at risk if, at its lowest level, your home is not at
least one foot above the nearest upstream manhole of the sewer main.
In this photo, the gray house is at risk. The pink house may be at
risk if it has a floor drain in the garage. Most likely, the house on
the left is not at risk.
People who live in hilly areas, especially those
on the downside of the street are most at risk.
The following step-by-step directions can help you find your sewer
lateral cleanout, your sewer lateral, the sewer main and the next
Where's my lateral?
1. First of all go to the curb and look for an "s" stamped into
It's sometimes painted green. If you can't
find one, look around your property line for something marked
"sewer." This may look like a smaller manhole. This is where
your curb cleanout is located.
img src="images/2-cleanouts384.jpg" width="133"
height="200" alt="Two cleanouts">
A cleanout may be close to your home
and not at the property line.
Newer or remodeled homes may have two cleanouts. If so,
you can draw a line between your cleanouts to see where
your lateral crosses your property. This is your upper lateral
Why is that important? You don't want to plant a tree right
over it or dig very deep over your lateral.
What if I don't have a cleanout?
You should have one put in, particularly if your home is
lower than the street level.
Where's the main?
2. Standing on your curb, look out into the street
and find the nearest upstream manhole in front of your
Connect it to the next nearest manhole so that the
dotted line passes in front of your house. The main is
located under the street at that dotted line.
Where does my
lateral join the main?
3. You can connect the dots between curb cleanout
and the dotted line between manholes in the street.
Your lower lateral is not going to connect where the
manhole is, but about 5-10 yards straight out from your
curb cleanout where it hits the dotted line where the
main line passes your property between the manholes.
Your home's upper lateral runs between the two
cleanouts. your lower lateral runs from the curb
cleanout to where the main runs under the street.
How do I know if my house is at risk?
4. Now that you have located where your lateral
joins your sewer main, locate the nearest upstream manhole
in the street.
Stand on the manhole
cover or stand at your house. Does your lowest elevation
or basement appear to be equal or at least 1 foot
above the manhole? Compare it with the elevation of the
manhole. Remember, your lowest drain may be in your
garage or basement where you have plumbing.
If the lowest elevation does not appear to be at
least 1 foot above the manhole, you may be at risk.
are unsure, put on a BPD anyway per your local requirements.
If you live in a flat area - you may have
difficulty figuring out which direction the sewer flows. You
can ask your plumber or call your sewer or sanitation district,
located in the phone book under Government listings for wastewater
If your home was built or remodeled after 1962,
local building codes require that your sewer system has a cleanout
and a backflow prevention device (also called a sewer relief device).