N.H. Rev. Stat. § 33:2
Municipalities and counties shall not issue any bonds or notes payable on demand. They shall provide for the payment of all loans issued under authority of this chapter except notes issued under authority of RSA 33:7, in annual payments which shall be so arranged that the amount of the annual payment of principal and interest in any year on account of any loan shall not be less than the amount of principal and interest payable in any subsequent year by more than 2 percent of the principal of the entire loan. The total amount of such payments shall be sufficient to extinguish the entire loan on account of which they are made at maturity. The first payment of principal on any loan shall be made not later than 2 years and the last payment not later than 30 years after the date thereof, provided, however, that no loan issued to pay for public work or improvement shall exceed the expected useful life of said public work or improvement as determined by the governing board or the city councils in the case of cities, or the county commissioners in the case of counties. Each authorized issue of notes or bonds shall be a separate loan. The amount of each payment of principal and interest on all loans shall, without vote of the municipality or county, be annually assessed and collected. Sinking funds and debt retirement funds for the payment of debt shall not hereafter be established.
RSA 33:2
1917, 129:2, 3. PL 59 :3, 4. RL 72:3. 1947, 5:1. 1949, 120:1. 1953, 258:1, par. 2, eff. Jan. 1, 1954.