A Phase I ESA meets the federal All Appropriate Inquiries rule if the inquiry is done within one year before you buy. Five parts also must be conducted or updated within 180 days before acquisition: owner and occupant interviews, lien searches, government records review, the site visit, and the environmental professional’s declaration.
Both limits come from 40 CFR 312.20, the EPA rule that sets the standard for All Appropriate Inquiries (AAI). Lenders can add their own limits on top of it.
What are the two clocks?
The rule sets an outer limit and an inner limit.
The outer limit is one year. Section 312.20(a) says AAI “must be conducted within one year prior to the date of acquisition of the subject property.”
The inner limit is 180 days. Section 312.20(b) says that, notwithstanding the one-year rule, five components “must be conducted or updated within 180 days of and prior to the date of acquisition.” EPA’s AAI page describes the same two timing rules.
So a report can be inside the one-year window and still be stale. If any of the five components is older than 180 days on the closing date, it needs an update.
Which five parts go stale at 180 days?
| Component | What it is | Rule |
|---|---|---|
| Interviews | Talks with past and present owners, operators and occupants | 312.20(b)(1), 312.23 |
| Lien search | Search for recorded environmental cleanup liens | 312.20(b)(2), 312.25 |
| Government records | Review of federal, tribal, state and local records | 312.20(b)(3), 312.26 |
| Site visit | Visual inspection of the property and adjoining properties | 312.20(b)(4), 312.27 |
| Declaration | The environmental professional’s signed declaration | 312.20(b)(5), 312.21(d) |
Each of the five can carry its own date. Because each one must fall within 180 days before closing, the oldest date among the five sets your deadline.
What does a dated example look like?
These dates are an illustration, not a real transaction. Assume all five components are finished on October 14, 2026, and the buyer plans to close on March 31, 2027.
| Date | What happens |
|---|---|
| October 14, 2026 | All five components are completed |
| March 31, 2027 | Planned closing, day 168. All five are inside the 180-day limit |
| April 12, 2027 | Day 180. The last day closing can happen without updating the five components |
| May 3, 2027 | Closing slips here. The five components are about 201 days old and need an update |
| October 14, 2027 | One year after the inquiry. Past this date, the inquiry no longer meets the one-year limit |
In this example, a slip from March 31 to May 3 does not force a new Phase I. The one-year window is still open. The five components need an update. The rule lets previously collected information be reused if it is updated for “relevant changes in the conditions of the property and specialized knowledge” (312.20(c)(4)).
If the closing slipped past October 14, 2027, the one-year limit would be missed and the inquiry would have to be redone. Ask your consultant for the exact component dates, then count 180 days forward from the oldest one.
Can you update an old Phase I instead of reordering one?
Yes, within the one-year limit. Section 312.20(c) lets AAI include information from an inquiry done earlier, as long as:
- the earlier work met the AAI requirements;
- it was collected or updated within one year before the acquisition;
- the five 180-day components were conducted or updated within 180 days before the acquisition; and
- the information is updated for relevant changes in property conditions and specialized knowledge.
A good update is not just a new cover date. The consultant has to redo or refresh each of the five components and note what changed. Our Phase I ESA service follows ASTM E1527-21 and includes the site inspection, records review, regulatory database search and interviews.
Can a buyer use a report that someone else ordered?
The rule allows it with conditions. Section 312.20(d) says AAI can include a report prepared by or for other persons if two things hold. The report must meet the rule’s objectives and performance factors. The buyer who wants to use it must review the information, do the additional inquiries the rule requires, and bring the 180-day components up to date.
In practice, a seller’s report helps the buyer’s consultant start. It does not replace the buyer’s own review and update. Ask the consultant whether you may rely on the report and who will be named as a user.
Which standard should the report follow?
Section 312.11 lists the ASTM standards that can be used to comply. They are E1527-21 for Phase I ESAs and E2247-23 for forestland and rural property. E1527-13 was allowed only until February 13, 2024. EPA says E1527-21 is consistent with the final rule and can be used to satisfy the AAI requirements.
If you hold a report that cites E1527-13 and the closing is after that date, ask your consultant to confirm the report still serves your purpose.
What should you tell the seller and lender?
Keep the timing simple.
- Ask the consultant for the date of each of the five components, in writing.
- Tell the seller and your attorney the oldest date and the day it hits 180 days.
- Ask the lender if it uses a shorter limit. Some programs set their own. For example, SBA loan rules require environmental reports to be dated within one year of the SBA loan number. See our article on SBA 7(a) and 504 environmental requirements.
- Build the closing calendar around the oldest date, not the report date.
For the full picture of a purchase, read our guide to commercial real estate due diligence and the page on historic building due diligence.
If you are planning an acquisition in Idaho, Eastern Washington, Eastern Oregon or Western Montana, call (208) 305-6245 or request a proposal.
