District of Columbia
Phase I Environmental Site Assessment
ASTM E1527-21 Phase I ESA to identify contamination risk before buying or financing commercial property.
What the work involves
A Phase I ESA reviews historical records, regulatory databases, site reconnaissance and interviews to identify recognized environmental conditions. Performed to ASTM E1527-21 and EPA's All Appropriate Inquiries rule, it helps buyers qualify for CERCLA liability protections and is commonly required by commercial lenders. It is performed by an environmental professional, who may or may not be a civil engineer.
Local conditions we plan for
- Riverine flooding (Potomac and Anacostia) and urban stormwater
- Combined sewer infrastructure
- Dense urban sites with historic structures
- High groundwater near rivers
Building code: 2015 IBC/IRC listed as adopted district wide, as amended by the DC Construction Codes (ICC adoption chart, April 2026).
When you need it
- Buying commercial or industrial property
- Lender requires a Phase I
- Former gas station, dry cleaner or industrial use
- Redevelopment of a brownfield
Frequently asked questions
How much does phase I Environmental Site Assessment cost?
Across the US, phase I Environmental Site Assessment usually costs $1,500 to $5,000 per site. Estimate from consultant and cost-guide sources, which commonly report about $1,500 to $5,000 for typical sites and more for large or complex ones.
How long does phase I Environmental Site Assessment take?
Plan on 2 to 4 weeks from signed proposal to stamped deliverables, longer if a site visit, soil testing or a permit review cycle is involved.
Is a permit required for phase I Environmental Site Assessment?
Often not on its own, but the findings frequently lead to work that does need a permit. We tell you which parts of the follow-up work your local building department will review, and can prepare those drawings too.
How do I verify an engineer's license in District of Columbia?
Engineers practicing in District of Columbia are licensed by the District of Columbia Board of Professional Engineers. You can confirm a license number and its status in the board's public license search before you sign a contract.
Which building code applies in District of Columbia?
2015 IBC/IRC listed as adopted district wide, as amended by the DC Construction Codes (ICC adoption chart, April 2026). Cities and counties can add local amendments, which is one reason to hire an engineer who works in your area.
What site problems do engineers see most in District of Columbia?
Common issues include riverine flooding (Potomac and Anacostia) and urban stormwater, combined sewer infrastructure, dense urban sites with historic structures and high groundwater near rivers.