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Homeowner’s Guide to Flood Preparedness

Homeowner's Guide to Flood Preparedness cover

The New York City Department of Environmental Protection created the Homeowner’s Guide to Flood Preparedness in an effort to help you protect your home and valuables against flooding from heavy rainfall and sewer backups. The guide offers helpful tips on a variety of flooding solutions and explains some of the most common causes of flooding.



Tips to Help you Protect Your Home from Sewer Backups and Flooding




Consider Check Valves and Other Backwater Protection
Under heavy rain conditions where the flow in the sewer rises and meets or exceeds the sewer’s capacity, basement plumbing fixtures such as toilets, sinks, and drains are vulnerable to sewer backups. A backwater valve, also known as a check valve, can prevent sewer water from rising up from the city sewer into your home through basement plumbing. During heavy rain, if water from the city sewer rises to the level of basement plumbing, the check valve closes and blocks sewer water from entering your home. While a check valve can be an effective device in preventing sewer backups, it is important to note that any wastewater from your toilets, sinks, or showers will not be able to leave your home while the valve is closed. You should not use these while the valve is closed because you can risk flooding your own property. If stormwater piping from the roof or outside drains are connected to the property’s combined house connection, the check valve must be placed so this water can flow out to the sewer even when the valve is closed. Drain plugs can be another option to prevent sewer backups into floor drains if they are present on the property. A licensed master plumber can help find the right solution and installation setup for your home.



Reduce Paved Areas to Improve lot Drainage
Water will pool in low-lying areas. Walk around your home and check that the ground is higher around the foundation walls and slopes down away from your home. If there are any low areas at the walls or foundation, you should address them by sloping the ground away from your home. Water can seep into your basement through existing cracks, so be sure to use a waterproof sealant to seal all cracks, both inside and outside your home. Another helpful tip is to reduce the stormwater runoff from your property. Water runs off concrete and asphalt almost immediately and can reach and overwhelm sewers quickly during heavy rains. Retaining and creating green and unpaved spaces around your home can help reduce flows into the sewer, increasing the sewer’s available capacity. There are alternatives to concrete, such as porous paving stones, which allow for uses like parking cars or patios while creating less stormwater runoff.



Protect Areas Below Street Level
Below street level spaces such as underground garages, basement doors, and other low lying areas are the most vulnerable to flooding. Reduce the risk of flooding your home’s vulnerable areas with the use of appropriate barriers or slope changes. Sandbags can be a cost effective option to block water from entering some of the spaces in your home. Other barrier options include window wells, flood walls around doors, and flood gates at driveway entrances. In addition, direct stormwater from your roof and porch away from low-lying spaces. A licensed professional engineer or architect can help find the right solution for your home.



Take Care of Your Sewer Connection
As a homeowner, you are responsible for the sewer connection from your home to the city sewer. A clogged or cracked sewer connection can prevent wastewater from flowing out of your home properly. Improper disposal of grease and cooking oil can clog your home’s internal pipes as well as city sewers. This can cause sewer backups in your neighborhood and home. In addition, never dispose of non-flushable items down the toilet. For more information on how to properly dispose of used cooking oil and grease, click here.



Help Keep Catch Basins Clear
The City is constantly working to maintain our 7,500 miles of sewers and 148,000 catch basins. You can do your part to help the sewers function at their best by keeping litter off the street and keeping catch basins clear. Catch basins are designed to collect stormwater through street-level gratings. Debris is captured in special collection areas which help keep it from entering into sewers and waterways. The New York City Department of Environmental Protection cleans and maintains these collection areas on a regular cycle. When debris covers and mats the street level gratings, stormwater cannot enter the catch basin and can pool around the area causing street flooding, even before the sewer is full. You and your neighbors can help reduce this type of flooding by disposing of litter properly and carefully removing leaves or trash from catch basins before or during a rain event.



Install Proper Downspout and Roof Drainage
Roofs and other drains that are directed toward your home can cause flooding. Directing stormwater from your roof away from the foundation walls of your home is critical in keeping your basement dry. Clean your gutters regularly to prevent stormwater from overflowing onto walls and connect downspouts to appropriate drains. Consider installing a rain barrel as an alternative method to capturing stormwater. You can then use this stored water for activities such as watering the lawn or washing your car. Please note that rain barrels alone are not sufficient to reduce flooding during a heavy rain event but when used as a tool in a comprehensive strategy can improve the overall performance of a property.


Other Tips

  • Consider homeowner’s flood insurance

    Homeowner’s insurance policies are all different, and some may not cover damages due to flooding. It is important to check with your insurance provider and consider purchasing a sewer backup or flood insurance policy or rider to your existing policy. This could cover the damage and cleanup costs resulting from sewer backups and flooding caused by heavy rain.

  • Elevate high-value items in your basement

    Put them on shelves or relocate to a higher floor.

  • Avoid traveling through flooded roadways

    Streets are designed so that stormwater flows toward catch basins. Sometimes tree roots, construction, and other street defects can cause small pools of water to form. These small pools usually dissipate shortly after it rains, however in more severe cases street flooding can occur. Never drive or walk through a flooded roadway.






Contact 311 to report roadway flooding or if you experience sewer backups or flooding not caused by conditions inside your home or property



Find out about the importance of water conservation and how you can help save water



Learn about different types of green infrastructure in New York City



View the Green Infrastructure Annual Report