FAQs

Floodplain management is the operation of a community program of preventive and corrective measures to reduce the risk of current and future flooding, resulting in a more resilient community. These measures take a variety of forms, are carried out by multiple stakeholders with a vested interest in responsible floodplain management, and generally include requirements for zoning, subdivision or building, building codes and special-purpose floodplain ordinances.

State and federal agencies, local communities and property owners have a role in reducing flood risk and helping communities become more resilient. From states providing strong model ordinances and communities adopting and enforcing higher-standard building practices to property owners elevating their homes, everyone can play a part in making communities safer and more resistant to flood disasters.

The National Flood Insurance Program (NFIP), managed by the Federal Emergency Management Agency, enables homeowners, business owners and renters in participating communities to purchase federally backed flood insurance. This offers an insurance alternative to disaster assistance to meet the escalating costs of repairing flood damage to buildings and their contents. Participating communities agree to adopt and enforce floodplain management ordinances to reduce future flood damage.

Missoula County staff routinely works with its agency partners to monitor flood hazards, river depths and flood warnings. In adopting higher regulatory standards and working with partners for hazard mitigation projects, we participate in the Community Rating System. The Community Rating System is a voluntary incentive program that recognizes and encourages community floodplain management practices that exceed the minimum requirements of the National Flood Insurance Program. That CRS benefit translates to a 15% countywide discount in flood insurance premiums.  

The Montana floodplain mapping program helps communities across the state identify flood risks. Identifying flood risk can help keep your home and local community safe from future flood events. Floodplain maps should be your go-to tool in learning about flood risks. Flood risks change over time, and floodplain maps will require periodic updates. It could be because of several things such as the age of the flood study, if there has been a lot of change or development in the area, or due to a flooding event. Flood studies now are done in collaboration with communities, DNRC and FEMA. Flood studies today use the best available data and technology. This includes high-accuracy topographic information, updated hydrologic data and modern engineering methods. Flood maps also help mortgage lenders determine insurance requirements and help communities develop strategies for reducing their risk.

Communities have an obligation to regulate the floodplain and enforce development standards as a condition for participating in the National Flood Insurance Program (NFIP). Flood insurance and funding for other projects such as mitigation and recovery is made available by the federal government, and communities are charged with ensuring that development in the regulatory floodplain is in accordance with federal, state and local laws. The purpose of the Missoula County Floodplain Regulations is to promote public health, safety and general welfare, to minimize flood losses in areas subject to flood hazards and to promote wise use of the floodplain.

Flood insurance premium costs depend on a variety of factors. In 2021, FEMA implemented a new risk rating methodology called Risk Rating 2.0: Equity in Action (RR2.0). Lenders will typically reevaluate their loans to reassess flood risk when a new map goes into effect. If you own a building in a high-risk flood area and have a federally backed loan, your lender will require you to have flood insurance, because the flood maps indicate a high flood risk. FEMA’s new rating methodology, Risk Rating 2.0, considers specific characteristics of a building to provide a more modern, individualized and equitable flood insurance rate, based on where the structure is built, how it is built (building characteristics), and what is built and covered (replacement cost and coverage).

The planning office is the official floodplain map repository for Missoula County and is open to the public for this purpose. Printed maps are available upon request. The county has committed to providing additional notice to all potentially affected property owners to make sure that those who need information about the changes in the floodplain maps have access to it. Sending a map with the FEMA floodplain designations to each affected landowner would be expensive and would confuse many landowners without additional context and explanation. Floodplain administration staff routinely help provide this information and are a resource for the public to navigate the FEMA flood hazard determinations. This is why we have hosted open houses and are making individual appointments with property owners.  

The floodplain study is a snapshot in time using climate data up until the study date. Future climate change and river channel migration is not considered in these FEMA floodplain maps. While we recognize this is a drawback, it does reinforce the need to continually update flood hazard information over time as the hydrologic cycle and landscape changes.  

Missoula County is concerned about adverse impacts caused by groundwater to both structures and septic systems. Site development reviews often identify potential effects of high groundwater. These issues can include crawlspace flooding and damage to subgrade enclosures. Groundwater is not often covered by the National Flood Insurance Program, and this adds to the importance of mitigating high groundwater by elevating mechanical equipment and avoiding construction of subgrade enclosures in susceptible areas.  

The floodplain mapping is based on fine scale variation across the landscape, such as the ground elevations at a specific site compared to how much a river or stream is expected to rise in the 100-year flood. This will result in different floodplain designations in a single neighborhood because even a difference of a few inches can result in land being affected by floodwater.  

The new FEMA floodplain study includes updated hydrology reflecting the amount of water during different flood scenarios. Current hydrology information, including seasonal water content, results in updated floodwater discharge volumes.  

Although some land next to the river will be above the ordinary high-water mark or even dry during seasonal runoff and certain flood events, this land can be below the elevation that FEMA has determined will be under water in a flood event, with a peak discharge that has a 1% chance in any given year.  

No, the Montana Department of Revenue determines taxable property values.  

No, both the city and county are undergoing the same map update from FEMA. Floodplain management and regulations differ between the city and county, so check with the appropriate jurisdiction for specific property questions.  

Historical flooding and local context may be referenced by FEMA and summarized in a Flood Insurance Study when preparing new floodplain maps. However, the flood study is based on probability of severe flooding based on calculated hydrology and hydraulics. An area with a 1% chance of flooding may experience a flooding event in subsequent years, or not at all over decades. Rivers and the water cycle change over time, and flood events over 100 years ago are not a major factor in establishing updated flood risk maps.  

Sanitation facilities and septic systems are overseen by the Missoula Public Health department and environmental health staff. Septic systems in the floodplain can pose significant public health risks. Replacement of existing or failed systems in the floodplain need to meet standards to ensure there will be no adverse impacts. Check with environmental health for a specific property.   

No, the highway was not built to FEMA levee standards, and it is not feasible to retrofit it to meet these standards.  

Missoula County promotes retrofitting existing structures, encouraging individual property owners to adequately insure their assets against flood risk, and requiring property owners to complete development in the floodplain to ensure it is reasonably safe from flooding. 

Flood insurance through the National Flood Insurance Program is the best way to protect from the financial losses associated with flooding. Additional grant or assistance opportunities can be available through the NFIP. Post-disaster financial assistance to communities and individuals can also be made available to communities that participate in the NFIP.  

Floodplain maps are created by FEMA to model the surface flow of floodwater in in the 1% annual chance flood event. Only a levee that has been accredited through the NFIP will be factored into the model for withstanding base flood forces. Other non-levee features, such as an unaccredited levee system, highway or railroad berm, are not recognized as providing adequate protection in the base flood. In particular, roads and railroads are constructed with gravel or rock bases to permit transfer of water, so the soil is not saturated. This prevents issues like frost heaving, for example. There are also drainage systems designed for interstate highways and other travel routes, such as culverts and drainage basins, to allow stormwater or floodwater through. We can expect the water to pass through many of these features and as a result, we cannot expect a railroad, highway or other non-levee feature to provide safety in the base flood. While some degree of protection may exist and can be recognized in how the floodway boundary is drawn, residents behind these features should be aware of the flood risk.  

Not necessarily. Participation in CRS does not automatically lead to increased regulations. The CRS program recognizes that standards that are higher than the minimums required by FEMA are often adopted by communities to better reduce flood damage and protect public health and safety.  The state of Montana (and therefore communities participating in the NFIP) has adopted two important standards that are higher than the minimum required by FEMA: 1) requiring two feet of freeboard and 2) mapping that is limited to allowing one half-foot floodway surcharge.  

The timeline for final adoption is under the purview of FEMA. As a participating community in the NFIP, the County will eventually receive a letter from FEMA with notification of the effective date and a statement that the County has six months to incorporate the maps into regulations as a condition for staying in the NFIP. There are several steps before we get to that point, such as a comment and appeals period, and potential regulatory adoption by the County, all of which hinge on the Department of Homeland Security (DHS) and FEMA communicating with the County about the timeline. Once we have more information, we will provide a more detailed timeline. 

Yes, the County can adopt higher regulatory standards. The process is to propose regulations with higher standards and obtain approval by the DNRC and FEMA. The County then conducts outreach and ultimately posts public notice. The commissioners then hold a public hearing to consider adopting the regulations. Here are two examples from Missoula County: 1) requiring engineered foundation walls for homes and 2) prohibiting new levees and rip rap in most situations.  

Flood insurance is a legal requirement for a home purchase when the home is in the FEMA-designated 100-year floodplain and is being financed with a federally backed mortgage. FEMA enforces this, not the County. 

Flood insurance policy holders should speak with their insurance agent for specific flood insurance questions. A claim can cover many things; however, there are coverage limits. Information about flood insurance can be found at floodsmart.gov. For a complete list of what is and isn’t covered, review the Summary of Coverage guide: https://agents.floodsmart.gov/sites/default/files/media/document/2025-07/fema-nfip-summary-coverage-brochure-12-2023.pdf