Updated: May 12, 2026
Location and Projects
Address
330 WATER STREET, Wilmington, DE, 19803
Use our bidding system to
request a quote
William G Day Company Plumber
William G Day Company, 330 Water St, Wilmington, DE (Employee: Denise M. Day) holds a Resident Contractor license and 5 other licenses according to the New Castle County license board.
Their BuildZoom score of 110 ranks in the top 4% of 8,071 Delaware licensed contractors.
Their license was verified as active when we last checked. If you are thinking of hiring William G Day Company, we recommend double-checking their license status with the license board and using our project planner to get competitive quotes.
William G Day Company Services
Start a project today:
William G Day Company Contact Information
Phone Number: (302) 427-3700
Edit
Address: 330 WATER STREET, Wilmington, DE 19803
Edit
Do you work for this business? Unlock this free profile to update company info and see who's viewing your profile.
Building Permits by William G Day Company
This is a sample of this contractor's permits. Click here to access their complete permit history.
Replacement duct work hydronic(boiler/radiant) install new hydronic piping for baseboard and toe-kick heater. install high velocity supply duct work for new bathroom. install exhaust duct for bathroom fan and exhaust duct for dryer vent. attach to building permit 202501289
Valuation:
N/A
Permit #:
202501889
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
New system hvac unit(s) duct work removing and replacing the existing diffusers and ductwork. installation of new vav's chilled water piping flex duct and low voltage wiring for sensors. insulating all piping and duct. attach to building permit 202509563
Valuation:
N/A
Permit #:
202509661
Status:
issued
Fee:
$258
Permit Type:
Replacement
Building Type:
Industrial
New plumbing inside underground plumbing gas test 12 fixtures 1 water heater(s) install rough plumbing and fixtures for new recreation building. attach to building permit 202407880
Valuation:
N/A
Permit #:
202506990
Status:
issued
Fee:
$210
Permit Type:
New construction
Building Type:
Exempt commercial
Replacement plumbing inside underground plumbing gas test 15 fixtures 1 water heater(s) underground rough fixture & gas piping for tenant fit out. attach to building permit 202414832 *(rev.9/2/2025: gas piping revision. addition of 1 tankless water heater to be used for the fertigation process.)
Valuation:
N/A
Permit #:
202501589
Status:
final
Fee:
$600
Permit Type:
Replacement
Building Type:
Industrial
Replacement hvac unit(s) hydronic(boiler/radiant) provide and install hydronic toe-kick heater assembly. refill and purge heating system. attach to building permit 202414866
Valuation:
N/A
Permit #:
202501033
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
New plumbing 2 fixtures remove plumbing for existing four restrooms. install new rough plumbing and fixtures for two exam rooms. attach to building permit 202415434
Valuation:
N/A
Permit #:
202502612
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Commercial
Replacement hvac unit(s) provide and install *4-ton air conditioner *100 000 btu gas furnace *4-ton evaporator coil. same for same. attach to building permit 202501033
Valuation:
N/A
Permit #:
202501512
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
New system hvac unit(s) duct work hydronic(boiler/radiant) install two air handlers with heat pumps. install complete duct system. install boiler with piping and new radiators. attach to building permit 202510126
Valuation:
N/A
Permit #:
202510993
Status:
issued
Fee:
$158
Permit Type:
Replacement
Building Type:
Residential
New system hvac unit(s) duct work install equipment and duct work for complete hvac system in new recreation building. attach to building permit 202407880
Valuation:
N/A
Permit #:
202506992
Status:
issued
Fee:
$447
Permit Type:
New construction
Building Type:
Exempt commercial
New system hvac unit(s) duct work install 5 ductless heat pump systems. install 1 ducted air handler with heat pump. attach to building permit # 202202772
Valuation:
N/A
Permit #:
202501963
Status:
issued
Fee:
$212
Permit Type:
New construction
Building Type:
Residential
New plumbing inside underground plumbing gas test 1 sewer laterals landlord work: install underground pvc sanitary piping and grease piping install dwv piping install backflow assembly install gas piping and connections as per drawings. related to building permit # 202206814
Valuation:
N/A
Permit #:
202302980
Status:
final
Fee:
$120
Permit Type:
New construction
Building Type:
Commercial
Replacement hvac unit(s) gas test installation of a new air conditioning unit and a new gas furnace. install new 1 main and manifold gas line
Valuation:
N/A
Permit #:
202505034
Status:
final
Fee:
$145
Permit Type:
Replacement
Building Type:
Residential
Replacement plumbing 2 fixtures modify rough plumbing and install new fixtures for kitchen renovation. attach to building permit 202414866
Valuation:
N/A
Permit #:
202501031
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
New plumbing 4 fixtures rough plumbing and fixtures for new first floor full bathroom and laundry. attach to building permit 202501289
Valuation:
N/A
Permit #:
202501887
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
Replacement hvac unit(s) install new carrier performance series 3-ton air conditioner 15 seer2 efficient. m#24sca536. same for same
Valuation:
N/A
Permit #:
202504496
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
N/A
New plumbing inside underground plumbing gas test 25 fixtures 4 water heater(s) install complete plumbing system for new restaurant including underground above floor gas piping and fixtures. related to building permit # 202210179
Valuation:
N/A
Permit #:
202217092
Status:
final
Fee:
$861
Permit Type:
New construction
Building Type:
Commercial
Replacement plumbing inside underground plumbing gas test 6 fixtures 1 water heater(s) building c- tenant fit out of storage facility. rough plumbing fixtures and gas piping. attached to building permit #:202313452 *(rev. 10/3/2024 modification of domestic water piping for new water heater & utility sink locations. addition of gas piping)*
Valuation:
N/A
Permit #:
202409422
Status:
final
Fee:
$285
Permit Type:
Replacement
Building Type:
Commercial
Replacement hvac unit(s) gas test installation of new air conditioning unit and new gas furnace (80 000 btu). installation of new refrigerant lines and new gas manifold
Valuation:
N/A
Permit #:
202508613
Status:
final
Fee:
$120
Permit Type:
Replacement
Building Type:
Residential
New system hvac unit(s) duct work complete mechanical system including rtus supply ductwork return ductwork exhaust ductwork and grease ductwork.hood installed by others related to building permit # 202210179
Valuation:
N/A
Permit #:
202217090
Status:
final
Fee:
$742
Permit Type:
New construction
Building Type:
Commercial
New plumbing 3 fixtures install rough plumbing/fixtures for new addition. attach to building permit 202413190
Valuation:
N/A
Permit #:
202501021
Status:
final
Fee:
$65
Permit Type:
Replacement
Building Type:
Residential
Similar Contractors See more
127
BZ Score
-
Avg Project
-
Projects
License # PL-0000510
Hockessin, DE
110
BZ Score
-
Avg Project
-
Projects
License # 79269
Smyrna, DE
110
BZ Score
-
Avg Project
-
Projects
William G Day Company Reviews
BuildZoom hasn't received any reviews for William G Day Company. Click here to be alerted when reviews are posted about them.
Recent Buildzoom Projects
Let us find you a plumber in your area today
We'll search our vast network of Plumbers and connect
you with one that meets your needs today.
Verified License
BuildZoom confirmed this contractor's license
William G Day Company License info
License Not Verified
| License # | 1996103733 |
| Status | Active |
| State | New Castle County |
| Type | Resident Contractor |
- When BuildZoom last verified this license, it had an expiration date of December, 2025. Check the current license status of William G Day Company with the State of Delaware Department of Finance: Division of Revenue
This is a sample of licensing data; click here to access a complete history.
Verified License
| License # | HL-0000001 |
| Status | Active |
| State | Delaware |
| Type | Hvacr Restricted |
- BuildZoom verified this license was active as of April 2026.
Verify this license's status for William G Day Company at the State of Delaware.
This is a sample of licensing data; click here to access a complete history.
License Not Verified
| License # | 1996103733 |
| Status | Active |
| State | New Castle County |
- When BuildZoom last verified this license, it had an expiration date of December, 2022. Check the current license status of William G Day Company with the State of Delaware Department of Finance: Division of Revenue
This is a sample of licensing data; click here to access a complete history.
License Not Verified
| License # | PA017110 |
| Status | Active |
| State | Pennsylvania |
| Type | Plumbing, Heating, Air Conditioning For Light Commercial And Residential Buildings. We Do New Installations And Retrofits. We Are Also Certified To Do Energy Audits. |
- When BuildZoom last verified this license, it had an expiration date of July, 2017. Check the current license status of William G Day Company with the Pennsylvania Office of the Attorney General
This is a sample of licensing data; click here to access a complete history.
Inactive License
| License # | NAT-F120847-1 |
| Status | Inactive |
| Nation | Environmental Protection Agency |
| Type | Renovation |
- According to the United States Environmental Protection Agency, the status of this license was at one point cancelled. However, this information may have changed. If this is your business, please update your license status.
Check this license's status for William G Day Company at the United States Environmental Protection Agency.
This is a sample of licensing data; click here to access a complete history.
Inactive License
| License # | PL-0000790 |
| Status | Inactive |
| State | Delaware |
| Type | Plumber |
- According to the State of Delaware, the status of this license was at one point cancelled. However, this information may have changed. If this is your business, please update your license status.
Check this license's status for William G Day Company at the State of Delaware.
This is a sample of licensing data; click here to access a complete history.
110
BuildZoom Score
Insured
| Insurer | Donegal Insurance Company |
| Insured up to | $2,000,000 |
723
Permits
- Building permit records show that William G Day Company has worked on 723 permitted projects.
William G Day Company Employees
DD
Denise M. Day
Office Manager
WD
William G Day
President