It's spring: Time to head to the Jersey Shore, smell the Atlantic, and daydream about buying a beach place.

Albert Slap and Bob Hubbell, long-ago Penn grads, have started a service in Florida they hope buyers and lenders will consult before signing off on 30 years of payments in these times of rising waters.

In some Shore neighborhoods, it could be a real estate buzz-killer.

Slap, a onetime public-interest lawyer whose Sierra Club lawsuit curbed Philadelphia's sewage dumping way back in 1979, and Hubbell, past spokesman for the accounting firm KPMG, own Coastal Risk Consulting L.L.C., which projects how much flooding a Shore property is likely to suffer over the life of a 30-year mortgage. Financial backers include Geronimo Ventures, Aspen, Colo.

Type an address, pay $49.95, and the partners churn out a 20-page flooding assessment. "With the advent of cloud computing, big publicly available databases, and [our] proprietary algorithms," coastal property "can be flood-scored quickly and cheaply," like a pricing report or a FICO credit score, Slap told me.

Trexin Consulting L.L.C. of Minneapolis is building software to speed Coastal's reporting, managing director Marvin Richardson, a former chief technology officer at global insurance broker Aon, told me.

Coastal uses data from the Federal Emergency Management Agency, National Flood Insurance Program, the U.S. Army Corps of Engineers Sea Level Rise Model, tidal, groundwater, and land-subsidence records. "It's not easy to put this all together" in a user-friendly report, Richardson told me. Insurers already use software that can warn them about neighborhood flood risk. But Coastal Risk, he said, "has the only algorithms that do this kind of flood analysis on a per-property-parcel basis."

Slap and Hubbell ran a sample report for me on a Shore landmark, the old brick Margate City Hall at 1 S. Washington Ave., vacated by city departments when Hurricane Sandy unloaded in 2012.

The Coastal report calculated City Hall was likely to be flooded at least 13 days, in all, over the next five years; 45 days over the next 10 years; and a total of six months from 2036 to 2045. At minimum.

Coastal towns need "affordable tools, easily available for our cities to begin to determine their vulnerability to sea-level rise," Cindy Lerner, mayor of Pinecrest, Fla., and past president of the Miami-Dade County League of Cities, told me. Local government has been reluctant to measure the risk, she said. Lerner was impressed by a Coastal assessment on a Norfolk, Va., property, and has ordered one for a public property in Pinecrest.

Will lenders keep risking a standard 30-year mortgage against that much water?

Some aren't panicking. "FEMA has flood maps that they use to price flood insurance," Vernon Hill, founder of Commerce Bank and now an investor and adviser for South Jersey-focused Republic Bank, told me. "Any new build or remodel must be above flood level." Standard mortgages for existing Shore houses remain "routine."

"We're telling the banks, maybe they should give a 15-year mortgage," said Slap. "They tell us, 'These people have paid 20 percent down, they have flood insurance, they have good credit ratings, they're not going to walk away.' We warn them a lot of the flooding is not storm-related - it's been happening on sunny days - it may not be insured. And we say they're going to start seeing a higher correlation between floods and defaults."