General Flood Hazard Information

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Crystal Lake Flood Information



A few areas of Crystal Lake are located in flood hazard areas. Most of these flood hazard areas are located around Crystal Lake itself, and along streams, such as Woods Creek and Crystal Creek.

The City has been studying the flooding issues in Crystal Lake. A separate flooding webpage has been created.

Information on whether your property is in the 100-year floodplain can be obtained by coming to City Hall and having an engineer assist you. Maps are available to look at as well as other flood-related information. The City also has Elevation Certificates for new development available back to 1990. Contact the Engineering Division at (815) 356-3605 for further assistance.

The following common sense guidelines can help you from the dangers of flooding:

Do not drive through a flooded area. More people drown in cars than anywhere else. Do not drive around barriers.
Do not walk through flowing water. Currents can be deceptive. Six inches of water can knock you off your feet.
Stay away from power lines and electrical wires. If your house is about to be flooded, turn off the power at the service box. Electrical current can travel through water. Electrocution is the second leading cause of death during floods.
Be alert to gas leaks. Turn off the gas to your house before it floods. If you smell gas, report it to a City official or your gas company. Do not use candles, lanterns or open flames if you smell gas or are unsure if your gas has been shut off.
Keep children away from the flood waters, ditches, culverts, and storm drains. Flood waters can carry unimaginable items that have dislodged themselves.
Culverts may suck smaller people into them rendering them helpless.
Clean everything that has been wet. Floodwater will be contaminated with sewage and other chemicals, which pose severe health threats.
Look out for animals, especially snakes. Small animals that have been flooded out of their home may seek shelter in yours.
Do not use gas engines, such as generators, or charcoal fires indoors during power outages. Carbon monoxide exhaust can pose serious health hazards.

Additional flooding precautions can be found in the Crystal Lake Emergency Preparedness Guide.

If your property is susceptible to flooding, there are many flood damage reduction measures you can employ, such as:
• Check sump pumps regularly. Many properties have reported damage due to flooded basements during flood events.
• Watertight seals can be applied to brick and block walls to protect against low-level flooding.
• Utilities such as heating and air conditioning systems, water heaters and other major appliances can be elevated to higher floors in the structure or on raised platforms.
• Temporary measures such as moving furniture and other valuables to higher floors or sandbagging exterior openings will also help.
• Elevating or relocating the entire structure may also be a feasible option.

All development within the 100-year floodplain (not just construction of buildings, but filling, excavation, fences, etc.) is required to obtain a permit from the City. Applications must be made prior to doing any work in a floodplain area. Please contact the Engineering Division to receive all the information you will need in order to properly develop in the floodplain at (815) 356-3605. You may report any illegal development activities to the above number as well.

The National Flood Insurance Program requires that if the cost of improvements to a building or the cost to repair damages (from any cause) to a building exceeds 50 percent of the market value of the building (excluding land value), the entire building must be brought up to current floodplain management standards for buildings in the floodplain. Building improvement projects include exterior and interior remodeling, rehabilitation, additions, and repair and reconstruction projects. Additionally, the cost of currently planned improvements will be added to the cost of previously made improvements and compared to the existing market value to determine if the improvements exceed 50 percent of the structure’s value. Please contact the Crystal Lake Engineering Division at (815) 356-3605 for further information.

If you do not have flood insurance, talk to your insurance agent. Most homeowner’s insurance policies do not cover damage from floods. Flood insurance is only available to those participating communities in the National Flood Insurance Program (NFIP). Because of the City's floodplain management programs that attempt to protect the community from the multiple flooding hazards, Crystal Lake is part of the NFIP and thus, residents are able to obtain flood insurance. Additionally, because the City participates in FEMA’s CRS program, flood insurance premiums are discounted.

Be sure to check your policy to ensure you have adequate coverage. Usually these policies cover the building structure, but not the contents. Contents coverage can also be obtained. There is a 30-day waiting period before flood insurance coverage becomes effective. Plan ahead; do not wait until a flood is predicted before purchasing flood insurance.

If you are building inside the floodplain, the purchase of flood insurance is mandatory if using a federally regulated and insured bank for a loan.

It is also important that residents who own or are considering the purchase of a home in the floodplain are aware of any mandatory flood insurance requirements by their lender. Flood Insurance is mandatory for federally backed mortgages and secured mortgages on buildings located in Special Flood Hazard Areas (SFHA) that are mapped on a Flood Insurance Rate Map (FIRM). The current Flood Insurance Rate Maps for Crystal Lake can be viewed at the FEMA Map Service Webpage:



While not always a possibility for every homeowner in the regulatory floodplain, there are a few options to try and eliminate the mandatory flood insurance requirement. If the grade surrounding your home is at an elevation higher than the established base flood elevation, a property owner can request documentation from FEMA called a Letter of Map Amendment (LOMA) that would eliminate the mandatory flood insurance requirement.

To obtain this documentation from FEMA, a licensed surveyor must measure the elevation of your home and surrounding grades and compare them to the established base flood elevations in FEMA’s Flood Insurance Rate Map and Flood Insurance Study.  The Elevation Certificate Form and a LOMA Application are completed by the surveyor and signed by the homeowner and the City Engineer before being submitted to FEMA. If approved by FEMA, a letter is sent back to the homeowner and the City acknowledging the removal of the structure and/or property from the floodplain.

As a reminder, this option is only available to homes that are situated in areas currently above the surrounding floodplain - new fill cannot be placed around a home to avoid mandatory flood insurance without proper permits and compensatory storage mitigation.

Floodplains play a valuable role in providing natural and beneficial functions to the area around, and including, Crystal Lake. Floodplains that are relatively undisturbed provide a wide range of benefits to both human and natural systems. These benefits provide aesthetic pleasure as well as function to provide active processes such as filtering nutrients. Floodplains are used as a means to filter farm chemical run-off so that these areas can maintain bio-diversity and ecosystem sustainability. Floodplains contain historic and archeological sites that provide opportunity for education and study. They enhance waterfowl, fish, and other wildlife habitats and provide feeding/breeding grounds. Lastly, floodplains provide natural erosion control and open space so further flooding damage does not occur.

As simple as it may sound, simply keeping smaller ditches and streams free of debris can dramatically improve the run-off capacity of low-lying areas, as well as greatly reduce the overland flow blockage that significantly contributes to flooding. It is illegal to dump materials into a waterway and violators may be fined. If you see someone in the act of dumping or see debris in one of our watercourses, please contact the Engineering Division at (815) 356-3605.

Sometimes, flooding can be predicted in advance, giving ample warning for preparation and evacuation. However, in the event of a flash flood due to a large rain event, you may have only minutes to execute your plan. Notify the Engineering Division at (815) 356-3605. Listen to the radio for local and National Weather Service Updates. You will also hear regular interruptions on local radio and television stations advising you of the situation.

If you would like more information regarding flood-related issues in Crystal Lake, here are some additional sources:
• National Flood Insurance Program website:
• City of Crystal Lake Community Development Department
100 West Woodstock Street
Crystal Lake, IL 60014
(815) 356-3605

To view information for the Fox River Flood Gauge near Algonquin, please visit this link:


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