Plumbing Contractor Permit Requirements in Wilmington, DE
Complete permit and license guide for starting a plumbing contractor in Wilmington, New Castle County, Delaware.
Not legal advice. Requirements may change — always verify with your local government authority before applying. This guide was compiled from public and official sources (last updated ) and has not yet been independently source-verified — confirm each requirement before acting on it.
Federal — start here
1 stopEIN (Employer Identification Number)
Required if you have employees or operate as an LLC or corporation. Free from the IRS.
Official government sourceFreeImmediate (online application)
Free
Immediate (online application)
State of Delaware
1 stopDelaware — No Sales Tax
Delaware has no state or local sales tax. Instead, Delaware levies a Gross Receipts Tax on the seller of goods or provider of services, based on total receipts. Register with the Delaware Division of Revenue.
Official government sourceFree (gross receipts tax registration)Immediate (online)
Free (gross receipts tax registration)
Immediate (online)
City of Wilmington / New Castle County
3 stopsDelaware Department of Labor — Master Plumber License
Plumbing contractors in Delaware must hold a Master Plumber License from the Delaware Department of Labor. Requires journeyman experience and passing a state exam.
Official government source$100–$200 (initial)4–8 weeks
$100–$200 (initial)
4–8 weeks
City of Wilmington Revenue Division — Business License
Wilmington requires a City Business License for all businesses operating within city limits. Fees are based on business type. This license must be renewed annually and displayed at your place of business.
Official government source$50–$500/year depending on business type and gross revenues1–3 weeks
$50–$500/year depending on business type and gross revenues
1–3 weeks
New Castle County / Wilmington Plumbing Permit (per project)
A separate permit must be pulled with the local building/plumbing department for each job. Inspections are required upon job completion.
Official government source$50–$300 per project1–5 business days
$50–$300 per project
1–5 business days
Terminus
Open for business — est. $400–$1,200 · 4–10 weeks to obtain all licenses
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Official Sources
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