How A Basement Floods
Sewer backup – More often than not, basement flooding is a result of overland flooding, infiltration flooding or sewer backup, or a combination of two or all three of these types of flooding. Sanitary sewage is generated by the use of toilets, sinks, drains and other home water uses. Because this type of sewage contains a high degree of contaminants and can pose a significant risk to human health and the environment, it requires treatment at sewage treatment facilities before it is released back into the environment. Sanitary sewage is collected through sanitary sewer laterals, which connect homes and buildings to underground sanitary sewer pipes. Storm sewage consists of excess surface water, resulting from rainfall or snow melt that has collected in streets, sidewalks, roofs and parking lots in urban areas. Various methods are used to channel this water to underground storm sewer pipes, including swales and catch basins. Although storm sewage is significantly cleaner than sanitary sewage, it can be contaminated with pet waste, salt and other contaminants picked up from city streets and other urban surfaces. In most cases, your neighborhood is serviced by underground sewage pipes that are either combined, separated or partially separated. These pipes carry either sanitary sewage, storm sewage, or a combination of both to sanitary sewage treatment facilities and nearby lakes, streams and rivers. Combined sewer systems convey a combination of sanitary sewage and storm sewage, which is conveyed to sewage treatment facilities before being released into local surface water, including lakes, streams and rivers. Combined sewers are designed to automatically bypass treatment facilities and re-route excess sewage to local surface water bodies when they become overwhelmed. This automatic bypass is called a combined sewer overflow (CSO), and it helps to protect sewage treatment facilities from damage and also helps to reduce the chances of sewer backup in buildings. However, as CSOs result in the release of raw, untreated sewage, they can have a significant negative impact on local surface water quality. Reduced water quality can have a negative impact on aquatic life, and can also reduce the recreational qualities of lakes and rivers. As homeowners’ weeping tile and downspout connections can contribute a substantial amount of water to the combined sewer, they can increase the chances that CSOs will occur. Separated sewer systems have two individual pipes that are designed to convey only sanitary sewage and only storm sewage. The separation of the different types of sewage allows municipal engineers to direct sanitary sewage to treatment facilities, while storm sewage is allowed to flow into nearby lakes, streams and rivers with less intensive treatment. In some cases, neighborhoods are serviced by partially separated sewers, which include sections that are combined and sections that are separated. Sewer backup can happen when municipal sanitary, combined, or storm sewer systems receive more water than they can handle. Excess water can cause the sewers to “surcharge,” and push water backwards through home sewer laterals and cause sewage to backup into the home through basement floor drains, toilets and sinks. Excessive surcharge in the municipal sewer can create high pressures around basement floors and the foundation, which can cause structural damage to the home. For example, excess pressure in pipes beneath the home can result in heaving of basement floors, especially when improper backwater valves are used. When weeping tiles are connected to the municipal system through sanitary sewer laterals or storm sewer laterals, sewage can be forced back into the weeping tiles, resulting in possible structural damage to the home. If a home has a storm sewer lateral and the municipal storm sewer surcharges, water can be forced out of the storm sewer lateral and can enter the sanitary sewer lateral, resulting in sewer backup in the home and can also contribute to sewer backup in the neighborhood.
What you need if your basement drain is backing up and flooding
So your basement floor drain is backing up and flooding. There’s water in the basement. First, you need to determine if it is local waste produced in your home that can’t get out due to a blockage in the main line leaving your home, or if it is waste from the sewer system coming back in (called a backflow). A blockage can occur if a portion of the line has broken, but generally a blockage is caused by roots that have grown into the line, or by something flushed down a toilet that has lodged in the drain pipe.When this happens, you will see evidence of your basement drain backing up as the lowest point in the system (generally the basement drain overflows) is where the evidence is visible. Chemical products may work to open the drain, but running a snake through the line is generally necessary. In the case of roots of invading the basement drain line, a power snake with sharp cutting blades must be used to cut through the roots. With your own local waste backing up it’s one thing, but when nasty, contaminated waste from hundreds of neighbors starts pouring into your home, it becomes a whole different issue. In this case, usually due to high levels of rainfall temporarily raising the water overall table, the system will be overwhelmed. If the lowest drain in your basement (or other shower drain or toilet) is lower than this temporarily raised water level, you will find your basement drain backing up. In some cases the pressure created by the raised water level is so great that water raw sewage will be spewing several feet into the room from basement drains.
There is only one way to prevent this particular condition of your basement drain backing up; the installation of a gate to keep the unwanted reverse flow out. Some of these gates are manual and must be manually inserted or manually turned closed. The best are automated solutions called “Backwater Valves“ or “Backflow Preventers” A Backwater Valve automatically senses a reverse flow (water flowing the wrong direction and back into your home) in your main line and completely closes it off from the sewer system outside. This prevents your basement drain backing up. As many know, what’s as stake is thousands of dollars of damage to the basement living space, not to mention the health hazards caused by the bacteria in the raw sewage produced by hundreds or even thousands of your neighbors. Some people simply insert a plug into their basement drain in an attempt to stop a basement drain backup, but in a case where groundwater comes in when there is not a mainline backup, the end result is also flooding. Additionally, the force of incoming water can simply push these plugs up and out of the way leaving you unprotected. A good automated backflow valve is the best solution to avoiding a basement drain overflow that lets water in the basement.
Having sewage back up into the home is an unpleasant and potentially unhealthy experience. The information contained here can help protect you from the hazards of raw sewage in your basement and give you practical methods for proper sanitation of your building should a back-up occur. Sewers can back-up into your basement from several paths during storms and it is the property owner’s responsibility to protect the building. Open floor drains are the major culprit, as are basement plumbing fixtures (toilets, sinks, shower drains, etc.). Floor drains are intended to allow water (from a broken water pipe, groundwater, etc.) out of your basement on (what should be) rare occasions. Otherwise, floor drains should always be capped off—a plumber can help you. If you must have plumbing fixtures in your basement, a licensed plumber can install devices that may protect you from backups (check valves, etc.) Open floor drains and basement plumbing fixtures put you and your property at risk during storms. Roots growing inside the lateral and blocking the pipe is the most common reason for sewer back-up not related to storms this, and any internal plumbing problem, is the responsibility of the property owner a private plumbing contractor should be called. In rare cases, the main sewer line can break, become blocked or be overwhelmed with stormwater resulting in area-wide backups.
If you have a backup, call a plumber. The plumber should be able to troubleshoot and fix almost all causes of a sewer backup. The county cannot recommend any plumber check your Yellow Pages. You may want to get more than one estimate and check references. Main sewer issues in other geographic areas in a county are handled by the local town/village.
Proper responses to sewer backups can greatly minimize negative health effects and property damage, destruction of your valuables and the risk of electrocution. Prompt cleanup of affected property can help minimize the inconvenience and damage. Most homeowner-type insurance policies DO NOT cover sewer backup damage. Ask your insurance agent for details on an inexpensive policy rider that can save you considerable expense and effort.
Please be aware of the risk of potential health and safety problems when addressing the cleanup of your home. Sewage and floodwaters can contain bacteria, fecal material, viruses and other hazardous microorganisms which can cause disease. These “germs” can be transmitted by touching contaminated items or by tracking them into uncontaminated areas on shoes. Children can be especially vulnerable. Odors from sewage backups are unpleasant but not harmful. The speedy removal and cleanup of sewer water is very important and necessary.