Regulatory – NHDES – All NHDES administrative rules are housed in this searchable library. You can sort by category or type of rule (proposed, adopted or certified) or by keyword. Adopted rules are not certified yet and must be read concurrently with the certified rule. Proposed rules are open to public comment for a period of time, and more information can be found in our rulemaking public notices. For more detail on our rules, see our Rulemaking and Enforcement page.