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 Floor Drain Standpipe
A standpipe installed in the floor drain will raise the overflow level. The standpipe is designed to hold back the water only if it would have flooded several inches deep. If the pressure builds to a higher point, it is better to let some of the water flow onto the floor in order to equalize the pressure, rather than taking a chance on having the sewer and floor broken. The standpipe may be left in place at all times if the floor drain is not needed.
It is not a good idea to plug the floor drain when the sewer surcharges and the flow begins to back up through the drain. If the drain is plugged, pressure in the piping under the floor may build up sufficiently to break the tiles and heave the basement floor.
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. 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 back up into the basement area.
Although an overhead system is very effective in eliminating basement backups, the plumbing charges required 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 case.
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. Even so, the overhead system in most cases is the most effective way to prevent basement flooding.