---
title: "What Is Phase I Environmental Site Assessment? | Calibre Glossary"
description: "A Phase I Environmental Site Assessment is a records review, site visit and interview process, performed under ASTM E1527-21, that identifies recognized."
url: https://calibre.multisites.ai/glossary/phase-i-environmental-site-assessment
publisher: Calibre Commercial Inspections
phone: "+1-208-305-6245"
email: Schedule@CalibreCBI.com
---

Environmental

# Phase I Environmental Site Assessment

A Phase I Environmental Site Assessment is a records review, site visit and interview process, performed under ASTM E1527-21, that identifies recognized environmental conditions at commercial real estate without sampling soil or water.

## Why it matters

Lenders commonly require a Phase I, and buyers use it to support landowner liability protections under CERCLA. An environmental professional must perform it. A Phase I is presumed viable for 180 days before acquisition, with some components updatable within one year.

Source: [store.astm.org](https://store.astm.org/e1527-21.html)

[Related Calibre servicePhase I Environmental Site Assessments](https://calibre.multisites.ai/cre-services/esa-environmental-site-assessments)

## Where we discuss it

-   [The Stack Is Still Standing — A Montana Landmark](https://calibre.multisites.ai/cre-inspector-insights/the-stack-anaconda-mt)
-   [Your First Commercial Sale: A Field Guide for the Residential Agent](https://calibre.multisites.ai/cre-inspector-insights/your-first-commercial-sale-a-field-guide-for-the-residential-agent)

## Ready for your next inspection?

Tell us about the property and your timeline. We will scope the right report and send a proposal.

[Request a proposal](https://calibre.multisites.ai/request-proposal) [(208) 305-6245](tel:+12083056245)