The Basics of Preventing Basement Flooding
By Jim Sulski
Summary: Even a brand new house can have flooding
in the basement. Water can enter through the sewer system or cracks in the foundation.
Jim gives homeowners tips on how to waterproof your basement.
April shower sometimes brings not only May flowers but flooded basements.
Basement seepage, and the occasional basement flood, are common home problems
and quirky ones: One house may be deluged with water in a basement yet a neighbor's
may stay bone dry, say officials. Even a new house can have basement water problems.
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And for those homes with a finished basement, even a small amount of water
can be extremely harmful, causing hundreds if not thousands of dollars in damage.
Basement seepage and flooding can also cause health concerns (if rainwater mixes
with sanitary sewer wastewater) or present a danger because of electrical shock.
Basements flood or leak because they're below grade or partially underground.
There are two ways water gets into the basement (and some homes suffer from
both). Here's the first: it can come up through a floor drain (or the drain
of a sink or a toilet) especially in neighborhoods were sanitary and rainwater
sewers are combined.
When rainwater over inundates a sewer system via drain openings on the street,
that water can backup into a home's drainpipe. This can result in serious flooding,
with several inches or several feet of water entering the basement through that
Water can also enter basements through cracks in the foundation walls. This
is known as seepage and because it's mostly rainwater, it's less of a sanitary
concern than a sewer backup. Seepage occurs when water collects on a sidewalk
or driveway next to a basement foundation wall, or when the ground around a
foundation wall becomes saturated with rainwater.
Seepage is not as damaging as floor drains backing up but can still cause major
damage to carpets, furniture, drywall and paneling in a basement.
Here is now to prevent water from getting in a basement.
For example, if water comes into a basement through a flood drain, a homeowner
can install a standpipe.
A standpipe is a wide diameter pipe inserted into the floor drain. Once the
below-ground water backs up into the drain, the water moves up into the standpipe,
staying contained in that pipe versus entering the basement.
Standpipes are either screwed or dropped into the basement drain opening. In
some cases, it may require a coupling available at most hardware or plumbing
A homeowner must decide whether to leave a standpipe in year-round, where it
could be in the way of walking path, or be around to place it in the floor drain
in the event of a rainstorm.
Another possible remedy to drain openings is a drain plug. The plugs are set
up to pop open again if there's too much water pressure so that the floor doesn't
Another prevention method is a sewer or check valve, installed on the underground
drainpipe that is connected to the basement floor drain.
There are manual and automatic valves. Basically, what they do is restrict
the flow of the water so that it runs away from the house. Expect to pay anywhere
from $2,500 to $6,000 to have one installed.
Another solution is an overhead sewer, which is more costly (they start at
about $10,000) but guarantees water will not back up into a basement. It especially
makes sense if the basement is finished and has a bathroom.
With this system, basement sewage is collected in a tank and then pumped out
by a motorized ejector pump through an overhead pipe that prevents any backup.
Homeowners should also check to make sure their home's downspouts are not tied
into their drainpipe. If the downspouts travel down into the ground, there's
a good chance that they are connected to the underground drain pipe.
The solution here is disconnecting the downspouts from the drainpipe. Start
by cutting a downspout about a foot above where it enters the ground. Install
an elbow connector at the cut, and then add an extension pipe to the elbow so
that water from the downspout is directed away from the house.
Remember not to point the pipe so that it floods your neighbor's driveway or
There's a couple of ways to address seepage coming in through cracks in the
walls and floors of the basement.
The most common is to have the walls and floor sealed, preferably from the
outside and the inside. If you hire a company to do that, carefully check them
out. Expect to pay several thousand dollars to have the basement sealed.
A homeowner can also opt for the less expensive method of sealing from the
inside, an easy job for the do-it-yourselfer. This requires cleaning the basement
walls, and then filling any large cracks with hydraulic cement. Then, you can
apply a coat of waterproof sealing paint to the interior foundation wall.
© by Jim Sulski. All rights reserved. January 27, 2005.
NOTE: This column is distributed by Real Estate Matters Syndicate,
PO Box 366, Glencoe, Illinois, 60022. This column may not be resold, reprinted,
resyndicated or redistributed without written permission from the publisher.
© 2005 by Ilyce R. Glink. Distributed by Real Estate Matters Syndicate.