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How do plumbers in Delaware get more customers from Google and AI search?
Short answer: Plumbers in Delaware get found online with a website that shows their license number, names the towns they serve such as Wilmington, Dover and Newark, and collects real local reviews. Licensing runs through the Delaware Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (Division of Professional Regulation).
- Licensing body: Delaware Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (Division of Professional Regulation).
- 335 businesses with staff in 2022, 46th of 50 states; 67% have fewer than 10 staff.
- Largest cities: Wilmington, Dover and Newark.
- Common words in local searches: “residential”.
- Coldest month January (about 35°F), warmest July (about 77°F), statewide average.
- Code edition: 2021 plumbing code.
Do plumbers need a license in Delaware?
In Delaware, the licensing body for this work is Delaware Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (Division of Professional Regulation).
License or registration types named by the state: Master Plumber.
- A Delaware license is needed to do plumbing work, even with a license from another state.
- Master Plumber needs 2 years under a master after a journeyman apprenticeship certificate, or 7 years under a master without one.
- Pass mark on the master exam is 70%.
- Insurance requirement was not stated on the board page.
Homeowners can check a license on the state lookup page. Put your number where they will look for it.
Contractor registration in Delaware sits with Delaware Department of Labor, Office of Contractor Registration, plus Division of Revenue business license. No general contractor competency license. Nearly all construction work, including concrete, remodeling and landscaping, must register before starting. Division of Revenue business license is required and was $75 per year in a 2018 tax tip. Renewal is each December 31.
What do homeowners in Delaware’s biggest cities search for?
Google autocomplete for plumber searches in each city (job-seeker searches removed):
Wilmington
- plumber wilmington de
- plumber wilmington delaware
- plumber wilmington island
- plumber wilmington ohio
- plumbers wilmington de residential
- plumbers wilmington ohio
- plumbers wilmington ohio residential
Dover
- plumber dover de
- plumber dover foxcroft maine
- plumber dover heights
- plumber dover kent
- plumber dover ohio
- plumber dover tasmania
- plumbers dover de residential
- plumbers dover foxcroft maine
Newark
- heating engineer newark
- newark plumbers merchants
- plumber newark de
- plumber newark ohio
- plumber newark on trent
- plumbers newark de residential
- plumbers newark delaware
- plumbers newark ohio
Middletown
- plumber middletown delaware
- plumber middletown ohio
- plumbers middletown ohio
Milford
- plumber milford haven
- plumber milford ohio
- plumber milford on sea
- plumbers milford haven
- plumbers milford ohio
- plumbers milford on sea
Across these cities, the words that come up most are “residential”.
Source: Google autocomplete suggestions, checked November 8, 2026. Suggestions change over time.
What does a year of plumber work look like in Delaware?
Publish each seasonal page four to six weeks ahead.
| Month | Avg temp | Jobs to plan for (our suggestion) |
|---|---|---|
| January | 35°F | water heater replacements, drain clearing after the thaw |
| February | 37°F | water heater replacements, drain clearing after the thaw |
| March | 44°F | water heater replacements, drain clearing after the thaw |
| April | 54°F | water heater replacements, drain clearing after the thaw |
| May | 64°F | remodel plumbing, outdoor spigots, sewer line inspections |
| June | 73°F | irrigation leaks, water heater checks, emergency leak calls |
| July | 77°F | irrigation leaks, water heater checks, emergency leak calls |
| August | 76°F | irrigation leaks, water heater checks, emergency leak calls |
| September | 69°F | remodel plumbing, outdoor spigots, sewer line inspections |
| October | 58°F | remodel plumbing, outdoor spigots, sewer line inspections |
| November | 47°F | water heater replacements, drain clearing after the thaw |
| December | 40°F | water heater replacements, drain clearing after the thaw |
Temperatures: NOAA NCEI nClimDiv statewide data. Job column: our planning suggestion, not survey data.
How many plumbing contractors compete in Delaware’s main cities?
| City | County | Businesses with staff | Residents per business |
|---|---|---|---|
| Wilmington | New Castle County | 178 | 3,251 |
| Dover | Kent County | 54 | 3,515 |
| Newark | New Castle County | 178 | 3,251 |
| Middletown | New Castle County | 178 | 3,251 |
| Milford | Sussex County | 103 | 2,558 |
Competition is tightest around Milford (Sussex County), with one business for every 2,558 residents, and loosest around Dover, at one per 3,515.
Source: US Census Bureau, County Business Patterns 2022 and County Population Estimates 2023. Counts businesses with paid employees only.
How many plumbing contractors are in Delaware?
The Census Bureau counted 335 businesses with employees in Delaware in 2022, in the category “Plumbing, heating and air-conditioning contractors”. That ranks Delaware 46th of 50 states, one of the smaller markets, and 0% of the US total. 67% of them have fewer than 10 staff, and 61 have 20 or more.
Together they employ 4,939 people, with an average yearly payroll of $973,030 per business. The three busiest counties hold 100% of them, so competition is packed into a few places.
With 1,031,890 residents (Census, July 2023), that is one business for every 3,080 people, against 3,051 nationally: close to the US average.
Delaware next to its neighbors
| State | Businesses | Residents per business | Under 10 staff |
|---|---|---|---|
| Delaware | 335 | 3,080 | 67% |
| Maryland | 2,048 | 3,018 | 70% |
| New Jersey | 3,500 | 2,655 | 81% |
| Pennsylvania | 4,136 | 3,134 | 77% |
Counties with the most plumbing contractors
| County | Businesses | Residents per business |
|---|---|---|
| New Castle County | 178 | 3,251 |
| Sussex County | 103 | 2,558 |
| Kent County | 54 | 3,515 |
3 of Delaware’s counties have at least one. Source: US Census Bureau, County Business Patterns 2022.
How big are they?
Businesses by number of employees, 2022: 166 with 1-4 staff, 58 with 5-9 staff, 50 with 10-19 staff, 37 with 20-49 staff, 24 with 50+ staff.
Where Delaware is growing
New homes and new owners bring new work. Delaware's population changed +4.0% from July 2020 to July 2023. The fastest-growing counties with 50,000 or more people:
- Sussex County: 263,509 people, +10.4% since 2020, 103 plumbing contractors
- Kent County: 189,789 people, +4.1% since 2020, 54 plumbing contractors
- New Castle County: 578,592 people, +1.3% since 2020, 178 plumbing contractors
Source: US Census Bureau, County Population Estimates, Vintage 2023.
Which code applies in Delaware?
Delaware uses the 2021 edition of the plumbing code (Per ICC April 2026 adoption chart; not cross-checked with the state). Homeowners rarely ask about code editions, but inspectors do, and a line on your service pages saying your work meets the current 2021 code answers the question before it comes up.
What should a Delaware plumber website show?
- Your license or registration number where people can see it, even where the state does not require it in ads.
- A service area list that names real counties and towns, for example New Castle County, Sussex County and Kent County.
- Seasonal pages published before April, so they are found when demand starts.
- Real reviews from local jobs, with the town named, and photos of your own work.
Delaware questions
Who licenses plumbers in Delaware?
Delaware Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (Division of Professional Regulation). A Delaware license is needed to do plumbing work, even with a license from another state. Master Plumber needs 2 years under a master after a journeyman apprenticeship certificate, or 7 years under a master without one. Pass mark on the master exam is 70%.
How many plumbing contractors are there in Delaware?
The US Census Bureau counted 335 businesses with employees in Delaware in 2022 in the category Plumbing, heating and air-conditioning contractors, and 67% of them have fewer than 10 staff.
Which county in Delaware has the most plumbing contractors?
New Castle County, with 178 businesses with employees in 2022 (Census County Business Patterns).
Which edition of the plumbing code does Delaware use?
The 2021 edition. Per ICC April 2026 adoption chart; not cross-checked with the state.
What do people in Wilmington search for when they need a plumber?
Google autocomplete for Wilmington shows searches such as “plumber wilmington de”, “plumber wilmington delaware”, “plumber wilmington island” and “plumber wilmington ohio”.
When is the busiest season for plumbers in Delaware?
Delaware’s statewide average runs from about 35°F in January to about 77°F in July (NOAA, 1991 to 2020).
Sources
- US Census Bureau, County Business Patterns 2022 (state and county files)
- US Census Bureau, City, Town and County Population Estimates, Vintage 2023
- NOAA NCEI, nClimDiv statewide temperature and degree days, 1991 to 2020
- Google autocomplete suggestions for the cities named, checked November 2026
- https://dpr.delaware.gov/boards/plumbers/newlicense/
- https://dpr.delaware.gov/boards/plumbers/faqs/
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