N.H. Rev. Stat. Ann. § 130-A: § 130-A:5

I. The commissioner shall investigate cases of lead poisoning in children reported under RSA 141-A whose blood lead level meets or exceeds 5 micrograms per deciliter of whole venous blood. The commissioner may also conduct investigations when there is reason to believe that a lead exposure hazard, as defined in RSA 130-A:1, XVI(b) and (d), for a child exists. Such investigations shall include, but not be limited to:
(a) Requiring additional information and periodic reports from the child' s health care provider, the owner or owner's agent of a leased or rented dwelling or dwelling unit occupied by a child, the owner or operator of any child care facility attended by the child, and any lead inspector, lead risk assessor, or lead abatement contractor involved in lead hazard reduction at the child's dwelling, dwelling unit, or child care facility.
(b) Inspections of dwellings or dwelling units or of any child care facility, and testing environmental samples.
(c) Issuing orders requiring the reduction of lead exposure hazards from a leased or rented dwelling or dwelling unit and from a child care facility, or issuing a notice to the owner of a dwelling or dwelling unit.
II. [Repealed.]
III. The commissioner may request health authorities to assist in such investigations.
IV. The commissioner may obtain an administrative inspection warrant under RSA 595-B if consent of the property owner or the owner's agent for an investigation or inspection is denied.