Thousands of Tampa Bay-area property owners could soon find themselves with new flood zone designations on their homes and businesses.The Federal Emergency Management Agency has completed a years-long study to update flood zone maps in Hillsborough, Pinellas, Pasco and Hernando counties. The maps represent the governmentís estimate of flood risk on a parcel-by-parcel basis and ultimately determine what people pay for flood insurance.Emergency managers say itís still too early to say how many property owners may be required to obtain flood insurance who donít have it now. Nor can they say how many could see their insurance rates fluctuate due to a new designation, either higher or lower."There is no formal number on how many parcels are impacted," said Rahim Harji, assistant Pinellas County administrator.So far, federal officials have released the what they call preliminary Flood Insurance Rate Maps for Pasco and Pinellas. Pasco County estimates that 28,000 parcels could see changes to their flood zone designations. Pinellas has not come up with an estimate for the number for properties affected. But preliminary maps show all but narrow strip of the northern and southern parts of the county face changes in flood zone designations.Hillsborough County expects to receive its new proposed flood zone maps in October. Hernando County officials did not return phone calls seeking comment.Pasco County is collecting feedback from residents, said spokeswoman Tambrey Lane. Pinellas County is holding a series of public meetings this week for residents to view maps and ask questions.The proposed changes can be reviewed on the countiesí websites in Pinellas and Pasco. In 2012, FEMA launched a coastal risk study for Citrus, Hernando, Hillsborough, Manatee, Pasco and Pinellas counties. It took six years to complete the study.The updates are based on revised coastal flood modeling, which can be affected by things such as changes in topography. They have nothing to do with evacuation zones during hurricanes.Counties must adopt or amend their floodplain management regulations to incorporate the new data. Once adopted, they will replace maps that are up to 15 years old.Hillsborough expects federal officials to hold its public meetings in early 2019, said Eugene Henry, hazard mitigation manager. He noted the review could possibly take longer than in other areas because of the numerous rivers in the county.If residents or government leaders disagree with the preliminary data, the Federal Emergency Management Agency will provide a 90-day appeal period. After that period, the agency will rule on the appeals before making the updated flood hazard information final.FEMA will give communities six months to adopt the revisions and update their floodplain management ordinances. The changes could require some homeowners who donít have it now to obtain flood insurance for properties carrying a mortgage with a federally regulated or insured lender.On the new maps, properties could either shift between low, moderate or high-risk zones. Some could even see their risk downgraded. Still, moving to a lower risk doesnít negate properties from flooding or storm surges."That does not mean you are free from a risk," warned Lisa Foster, Pinellas Countyís floodplain coordinator. She urged homeowners to call their insurance agents before the changes become final.When property owners in lower zones need to buy flood insurance, they are "usually eligible for highly reduced preferred risk rates," Foster said. Lynne McChristian, Florida representative for the Insurance Information Institute, said 20 percent of flood claims are paid to people in low to moderate risk zones. "If you were in a flood zone before and youíre not in a flood zone now, I donít think you should kid yourself into thinking youíre scot-free," she said.If a home moves from a low-risk area to a high-risk area, the premiums will increase to reflect the new risk designation. But there is a National Flood Insurance Program for "newly mapped" homes that allow homeowners to receive reduced rates for the first 12 months after they are rezoned.According to Dolores Glass, senior communications manager for Wright National Flood Insurance, the reduced rate will increase by 18 percent each year until it is at the full risk rate to give people a chance to adjust. Wright has the highest number of federal program policyholders in the country.The rate will increase 25 percent each year for businesses and second homes.Contact Mark Puente at [email protected] or (727) 892-2996. Follow @MarkPuente.