Basement flooding from cracks and openings in basement walls can be prevented only if the walls and floor are in good condition. Footing drains and sump pumps are desirable in preventing flooding from this source. This type of flooding is beyond the scope of this discussion. Preventing backups from the sewage collection system can be categorized as short-term and long-term measures.
- Preparation is the key to emergency prevention of basement backups. When backup is imminent, sandbags should be placed on the floor drains and in the plumbing fixtures (toilets) to minimize the amount of water backing up into the basement. An alternative to sandbags would be a rubber plug. These are listed in the USA Bluebook catalog and can also be found at hardware stores and plumbing suppliers. The prices for three-inch and four-inch plugs are typically less than $5.
- Immediately stop all water use in the household when backup conditions are imminent or are occurring.
- Call the city or sewer district immediately and inform them of the problem. There may be blockages, pump malfunctions, or other problems that can be corrected without much delay.
Long-term preventive measures are necessary if basement backups from the collection system are likely to occur. The following are suggested preventive measures:
- Plumbing modifications may be made. Basement floor drains may be permanently plugged and a sump pump installed. Basement showers and toilets can be modified to pump into the household sewer at or near ground level. Usually water will not back up into plumbing fixtures at the main floor level. The problems occur because of the lesser degree of elevation change between the basement floor and the main sewer line. Again, when sewers are surcharged, minimize the use of water as the sewers can't carry it and it will be discharged into the environment.
- Another type of plumbing change would be the installation of check valves. This type of valve prevents the reversal of flow or backup of sewage into the basement. Your plumbing contractor should be able to obtain and install this type of valve. These may be obtained from local suppliers of water and wastewater products or plumbing supplies.
- These are also listed in the USA Bluebook catalog as plastic backwater valves. The prices for three-inch and four-inch valves are in the $30 to $60 range. Another type of valve listed is the sewer relief valve and cleanout. This valve is installed outside the house and allows overflow at a predetermined level, thus preventing backup of sewage into the basement. This valve is also in the $40 range.
- A third listing in the Bluebook is the elder valve, which is a valve that can be manually shut off or screwed down to reduce flow. It also serves as a cleanout. The price of this valve is approximately $80.