Plumbing and HVAC rules in Delaware

What the state says about plumbing and heating and cooling work, with the page each rule comes from. It's a summary of the published rules, not legal advice, and your city or county can have rules of its own.

Checked September 23, 2026

Plumbing licensing

In Delaware, master plumber licenses are held by individuals and issued by the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners.^{1, 2, 3}

Heating and cooling licensing

Delaware's plumbing and HVACR board issues a Master HVACR license for the full trade, or a Master HVACR Restricted license limited to one specialty such as forced-air heating, air conditioning or refrigeration.⁴

Plumbing and mechanical codes

Delaware's plumbing code is the 2021 International Plumbing Code with state amendments, in effect since August 11, 2022.⁵

Permits to replace a water heater, furnace or AC

Delaware's plumbing code requires plumbing permits, but the Division of Public Health requires no permit or fee to replace existing equipment, and it names water heaters. Relocated or new equipment needs a permit, and permits for heating and cooling work are local.⁵

Backflow testing

If your home has a backflow preventer, your water utility can tell you whether it needs testing and who can test it.

Sources

What plumbing and HVAC work costs in Delaware

Published national ranges for plumbing, water heater, sewer, AC, heat pump and furnace jobs, and a planning estimate for your own job.

Plumbing, heating and cooling costs in Delaware

Contractors in Delaware

141 plumbers and heating and cooling contractors are listed in Delaware. 38 hold an active USDOT registration. Browse them by county, or ask for quotes and we'll pass your job to contractors near you.

Cite this page

“Plumbing and HVAC rules in Delaware.” PlumbingInformationSite.com, updated September 27, 2026. https://plumbinginformationsite.com/de/rules/