Phase I ESA validity calculator

Short answer: A Phase I is good for 180 days, or one year with an update, counted from the work dates, not the report date. Under 40 CFR 312.20, 5 parts must be done or updated within 180 days before you take title and all work within one year; later closings need a new Phase I. SBA’s own test: a report dated within one year of the loan number date.

The federal rule: 180 days and one year

The All Appropriate Inquiries (AAI) rule is the U.S. Environmental Protection Agency (EPA) regulation that defines the inquiry a buyer must complete to qualify for the landowner liability protections under the federal Superfund law, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). A Phase I Environmental Site Assessment (ESA) performed to ASTM E1527-21 is the usual way to carry it out. Both of the rule’s clocks run to the date of acquisition, which 40 CFR 312.10 defines as the date you acquire title.

EPA explained the one-year limit by saying that “a year is sufficient time for conditions at a property to change” (70 FR 66083). Because both clocks run to the closing, a Phase I has no printed expiration date. An older report also keeps some value: under 312.20(c), a new inquiry may reuse its information if it is brought within both clocks and updated for changes at the property and for what the buyer and the Environmental Professional (EP) know.

Our guide to the Phase I ESA 180-day rule and how long a Phase I is good for explains the rule in more depth, including what to do when a closing slips.

Which date starts the clock

Not the date on the cover. ASTM E1527-21, the standard practice EPA recognizes for meeting AAI, says the report date generally does not show when the parts were done and should not be used to judge either limit (section 4.6.3). The report is written after the work, so counting from its date makes a report look younger than it is. Answers that count from the report date or from the site visit alone do not follow the standard.

• 180-day test: the earliest of the 5 dates. E1527-21 requires the report to list the dates of the interviews, government records review, site visit and declaration (4.6.1). The lien search is your responsibility as the user, and the standard requires the report to list its date only if you hired the EP to run it. If you or your title company ran it, that date counts too.
• One-year test: the oldest date of any work in the inquiry, such as the historical records review (4.6.3; 312.20(a)). An update usually refreshes only the 5 parts, so for an updated report this date comes from the original report.
• Using the calculator: enter the earliest of the 5 dates in the first box. If any other work in the report is older, such as the historical records review, enter that date under “Oldest work in the report”. For an updated report, enter the original report’s earliest date there. Left blank, that box takes the first date.

The calculator counts calendar days. Its one-year date is the same calendar date one year after the oldest work you entered (366 days when a February 29 falls inside; a February 29 start runs to February 28). It returns one of three results:

• Usable as is: the closing is no more than 180 days after the earliest of the 5 dates and not past the one-year date.
• Needs an update before closing: the closing is 181 days or more after the earliest of the 5 dates and not past the one-year date.
• Needs a new Phase I: the closing is past the one-year date, even if it is within 180 days of the 5 dates.

The regulation does not say how to count the days, so do not plan a closing for the last one. If the closing date has already passed, the calculator says so: EPA’s guidance says a buyer cannot perform all appropriate inquiries after acquiring the property (EPA Common Elements guidance, p. 5).

Worked examples

The first three rows follow one report as its closing date moves; the last is an SBA loan. Enter the same dates in the calculator to reproduce each result while its closing date is still ahead.

SBA loans: one year from the loan number date

For U.S. Small Business Administration (SBA) 7(a) and 504 loans, the rule is in SOP 50 10 8.1, published September 25, 2026 and effective October 1, 2026 (SBA posts it as a Word file). SBA Information Notice 5000-882227 applies it to applications received on or after October 1, 2026; earlier applications stay under the 2025 SOP, which used the same one-year rule from June 1, 2025.

Section A, Chapter 5, Paragraph E.3 says “Environmental Investigation Reports must be dated within one year of the date of issuance of the SBA loan number.” Appendix 4 applies the same test to the Environmental Questionnaire, the Records Search with Risk Assessment (RSRA), the Transaction Screen and the Phase I. Paragraph E.6.a requires the lead risk assessment and drinking water tests at pre-1978 child-occupied facilities to be conducted within one year of that date.

For a Phase I, Appendix 4 says SBA applies its test “notwithstanding the EPA’s regulations on updating Phase I ESAs after 180 days,” and warns that parties “may still wish to strictly comply with EPA’s regulatory timeframes to avoid jeopardizing legal and regulatory protections.” SBA’s test decides what SBA will accept for review; whether the buyer’s inquiry meets AAI still depends on the federal clocks. Because the SOP speaks of the report being “dated” and never mentions component dates, the safe course is to keep the oldest work in the report within one year of the loan number date too.

SBA’s reliance letter allows for updated reports: the Appendix 5 letter, required for every Transaction Screen, Phase I and Phase II, has a box for “A Phase I (or an Updated Phase I).” Our guides to SBA environmental requirements and the SBA reliance letter explain which report a loan needs and how the letter works.

To run SBA’s test in the calculator, tick the SBA box and enter the report date and the SBA loan number date, actual or expected. The check reads the report date, as the SOP does, and also compares the oldest date you entered (the oldest work, or the earliest of the 5 dates if that box is blank) with the loan number date, the safe course described above. If the report is dated after the loan number, the calculator flags it, because the SOP does not say whether that order matters; confirm with the lender. When the closing needs an update or a new Phase I and falls more than one year after the loan number date, the calculator also gives the last date that new report can carry, because it must be dated within one year of the loan number date too.

Other lenders set their own limits

The federal clocks govern the buyer’s all appropriate inquiries, one of the requirements for CERCLA protection. They do not bind a lender, and apart from the SBA option the calculator applies no lender’s own rule. Freddie Mac multifamily, for example, wants the report dated within 6 months before the full underwriting package is delivered (Seller/Servicer Guide, Chapter 61, 61.2(b)), and banks and credit unions set limits in their own credit policies. The Phase I ESA 180-day rule guide compares the published lender and agency rules; ask your lender for its limit in writing.

What an update involves and costs

An update redoes the 5 time-sensitive parts and folds in what has changed since the original work, as 312.20(c)(4) requires: new interviews, a new government records search, a new site visit and a new EP declaration, plus a current lien search (yours, unless you hire the EP to run it). It does not reset the one-year limit on the rest of the original work.

Our Phase I update is $595 for a report we prepared and takes 4 business days from authorization and confirmed site access. It includes an updated report signed by an Environmental Professional who meets 40 CFR 312.10 and the SBA Appendix 5 reliance letter; each additional reliance party is $99, with the letter issued within 1 business day of a complete request. We can usually update another firm’s report if it meets E1527-21 and we can perform the update ourselves; we confirm scope and price within 1 business hour of seeing it.

Past one year, you need a new Phase I, which with us is $1,495 for a standard-scope property and 5 business days from authorization and confirmed site access. The new inquiry can still draw on the earlier report’s information, with a current investigation of conditions (E1527-21, 4.7.1). Our guide to how long a Phase I takes helps you pick the order date.

Can you use a previous Phase I, or one prepared for someone else?

Yes, within the same clocks, if you do your part. Under 312.20(d), you may use a report prepared by or for someone else, such as the seller, if it meets the rule’s objectives and performance factors and you review it, complete your own inquiries into specialized knowledge, purchase price compared with fair market value, and commonly known information (312.28 to 312.30), and update it as needed. Enter its dates in the calculator the same way.

A right to rely on that report is a separate contract matter: E1527-21 conveys no right to rely on a prior assessment (4.7.1), so you and your lender need a reliance letter from the firm that wrote it, and SBA lenders need the Appendix 5 letter. A reliance letter does not satisfy AAI for you. For most buyers the relevant CERCLA protection is the bona fide prospective purchaser (BFPP) defense, which also requires your own inquiries and, after closing, continuing obligations such as reasonable steps and cooperation (42 U.S.C. 9601(40)). Whether you qualify is a question for your attorney. The Phase I ESA 180-day rule guide covers the seller’s-report case, and our reliance letter guide covers the letter.

Sources

1. 40 CFR 312.20, All appropriate inquiries, eCFR (current as of October 16, 2026), accessed October 2026.
2. 40 CFR 312.10, Definitions, eCFR, accessed October 2026.
3. Standards and Practices for All Appropriate Inquiries, final rule, 70 FR 66070 (November 1, 2005), U.S. Environmental Protection Agency, Federal Register, accessed October 2026.
4. ASTM E1527-21, Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process, ASTM International (public scope and significance sections), accessed October 2026.
5. Enforcement Discretion Guidance Regarding Statutory Criteria for Those Who May Qualify as CERCLA Bona Fide Prospective Purchasers, Contiguous Property Owners, or Innocent Landowners (“Common Elements”), U.S. EPA, July 29, 2019, accessed October 2026.
6. SOP 50 10 8.1, Lender and Development Company Loan Programs with Technical Policy Updates, U.S. Small Business Administration (effective October 1, 2026; .docx), accessed October 2026.
7. SBA Information Notice 5000-882227, Issuance of Technical Updates to SOP 50 10 8.1, U.S. Small Business Administration, September 25, 2026, accessed October 2026.
8. Multifamily Seller/Servicer Guide, Chapter 61: Environmental Requirements, Freddie Mac (Guide Bulletin update August 25, 2026), accessed October 2026.
9. 42 U.S.C. 9601, Definitions, United States Code, 2024 edition, U.S. Government Publishing Office (govinfo), accessed October 2026.