Village of Arlington Heights

Basement Flooding


Basement Flooding

When a heavy rainfall causes the quantity of storm water to exceed the capacity of the Village's sewer system, pressure builds up in the system and water can back up into unprotected basements. If your basement is affected by backups caused by surcharging in the system, there are several courses of action available to you.

Install A Backwater Valve
A mechanical valve or a check valve will help prevent basement flooding. A check valve that closes automatically when flow through the sewer line reverses may be installed either outside the house or inside the basement, depending on your specific situation. A mechanical valve is normally located outside the basement and must be opened or closed manually.

A Word of Caution:
Check valves installed in sewer lines sometimes become clogged with debris and fail to close completely. When this happens, the valve will slow down the flow of sewage but will not stop it completely. For this reason, a valve should not be depended upon completely, and the valve should always remain accessible for service and repair. It is usually a good idea to install two valves, in series, in order to reduce the chances of a clog occurring. Remember that when a valve is installed in a house sewer, the house plumbing cannot be used during a storm when the valve is closed to prevent basement flooding.

Install an Overhead Sewer System

An overhead sewer is a system in which all sewage from above-ground level flows by gravity to the Village sewer, but all sewage and storm water collected below grade in the basement must be pumped up to the house sewer at a connection near the basement ceiling. There are no direct connections between the main sewer system and the basement, so there is no way for the sewage to backup into the basement area.

Although an overhead system is very effective in eliminating basement backups, the plumbing charges required usually make it a costly solution. However, it is still a good choice for homeowners who have a substantial investment in finished basements or who have valuable equipment or storage items housed in the lower level.

One disadvantage of an overhead system is that the pumps used to force the water up from the basement level will not operate during a power outage, so overflow could occur if the power is out for an extended time. Installation of a backup generator is one approach to overcome this problem. Even so, the overhead system in most cases is the most effective way to prevent basement flooding.

When excessive ground water is allowed to accumulate around the foundation of the house, water may seep into the basement through the basement floor and walls. There are three common problems which may cause water to build up around the foundation.

Footing Drains Most basements have a footing drain around the outside wall which is designed to collect ground water in the soil and keep it from seeping through cracks in the basement floor and walls. In older homes, the footing drain is connected directly to the house sanitary sewer. When a basement develops leaks in the floor or walls, it is often due to blockage or breakage of the footing drains. When the footing drains are not functioning properly, the ground water collects around the foundation of the house instead of draining into the sewer system. If your basement is flooding due to problems with the footing drains, there are three possible solutions:

1. Disconnect the footing drains from the sanitary sewer and install a sump pump 
2. Clean the footing drains

Exterior Grading
Basement floor and wall leaks can also be caused by excessive amounts of ground water collecting around the basement walls due to improper grading. It is extremely important that the ground around the foundation be sloped away from the house for at least several feet wherever possible in order to prevent excessive amounts of water from accumulating in the soil next to the house.

Downspout Drainage
If the downspouts connect with the house drain or sewer, basement flooding can occur when the underground connections become broken, causing the water to seep through the foundation in the vicinity of the break. Also, if the downspout is emptying into a sewer which is clogged by tree roots or other obstruction, the sewer may back up into the basement.

You may find it advisable to disconnect the downspouts and let the rain be absorbed into the ground instead of entering the house sewer. If rainwater from downspouts is being discharged onto the ground, be sure to use splash blocks or other means to direct the flow of water well away from the house foundation.
Arlington Heights is dotted with a network of creeks, wetlands, reservoirs, and detention/retention basins. These bodies of water contribute a sense of beauty and tranquility to the community, as well as provide a habitat for fish, waterfowl, and vegetation. But these bodies of water have a very practical use as well. They are essential components of the Village's multi-faceted flood control program.


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