Assessors estimate rent, vacancy and expenses, then apply a capitalization rate. Condominiums are divided into separate properties whose values move with individual sales. The same collection of kitchens, bedrooms and parking spaces can carry a different aggregate value once it is divided among hundreds of deeds.⁹ [Appendix C]
The valuation appendix follows 870 rental apartments at West End Yards, Arbor View and The Pines, and Portwalk. Their owners pay substantial taxes. The analysis also finds a large gap between the current whole-property assessments and a range of hypothetical condominium sellout values. That gap reflects real conversion costs, tenant issues, sales commissions, financing and years of risk. It also makes the city’s assumptions about rent, vacancy, expenses and capitalization rates a matter of public interest.¹⁰ [Appendix C]
The appendix is an invitation to inspect the assumptions, rather than a verdict that developers received a secret bargain. Portsmouth’s own mass-appraisal model uses a 40 percent base expense ratio for apartments and a 6.5 percent base capitalization rate, adjusted for property quality and risk. Small changes in either number can move an assessment by millions.⁹ [Appendix C]
This matters because growth can lower the tax rate while rising residential values still push particular tax bills higher. New apartments in the West End do not mechanically raise taxes in the South End. Revaluation reallocates the levy according to relative market value. A scarce historic house may absorb more of the burden when its value climbs faster than commercial or rental property, even while new construction expands the overall base.⁸ [Appendix B]
That is the Portsmouth arithmetic now.
The city drew value for decades from pipes, stations, buildings and streets constructed for a smaller, cheaper place. Much of that machinery outlasted its expected life. The waterfront grew more precious while the infrastructure beneath it grew older. Climate risk, labor costs and public expectations rose together.
The city now wants modern infrastructure without ugliness, historic preservation without fragility, public safety without vacancies, strong schools without unaffordable taxes, housing without displacement and climate protection without surrendering the view. Each ambition has merit. Together they form a financial program.
A single public ledger would make the choices easier to see: major projects, full costs, funding sources, likely grants, annual debt service, utility-rate effects, operating expenses, valuation methods and any tax exemptions, abatements or special treatment. Then residents could argue over choices instead of estimates presented one meeting at a time.
At the end of Mechanic Street, Portsmouth still becomes almost too beautiful for arithmetic. The harbor opens beyond the old houses. The stones at Point of Graves keep leaning toward the water.