RFO
RFO Version Available
The Revolutionary FAR Overhaul has published a revised version of this clause. The RFO version supersedes the eCFR text below for contracts using the RFO model; see the RFO deviation for applicability.
View RFO version52.236-2 Differing Site Conditions. As prescribed in 36.502, insert the following clause: Differing Site Conditions (APR 1984) (a) The Contractor shall promptly, and before the conditions are disturbed, give a written notice to the Contracting Officer of (1) subsurface or latent physical conditions at the site which differ materially from those indicated in this contract, or (2) unknown physical conditions at the site, of an unusual nature, which differ materially from those ordinarily encountered and generally recognized as inhering in work of the character provided for in the contract. (b) The Contracting Officer shall investigate the site conditions promptly after receiving the notice. If the conditions do materially so differ and cause an increase or decrease in the Contractor's cost of, or the time required for, performing any part of the work under this contract, whether or not changed as a result of the conditions, an equitable adjustment shall be made under this clause and the contract modified in writing accordingly. (c) No request by the Contractor for an equitable adjustment to the contract under this clause shall be allowed, unless the Contractor has given the written notice required; provided, that the time prescribed in (a) above for giving written notice may be extended by the Contracting Officer. (d) No request by the Contractor for an equitable adjustment to the contract for differing site conditions shall be allowed if made after final payment under this contract. (End of clause) [48 FR 42478, Sept. 19, 1983, as amended at 60 FR 34761, July 3, 1995]
36.502
The contracting officer shall insert the clause at 52.236-2, Differing Site Conditions, in solicitations and contracts when a fixed-price construction contract or a fixed-price dismantling, demolition, or removal of improvements contract is contemplated and the contract amount is expected to exceed the simplified acquisition threshold. The contracting officer may insert the clause in solicitations and contracts when a fixed-price construction or a fixed-price contract for dismantling, demolition, or removal of improvements is contemplated and the contract amount is expected to be at or below the simplified acquisition threshold.
Prescription data sourced from eCFR as of 2026-06-10 03:16 UTC.
Cross-references within the prescription are not resolved automatically.
Regulatory Stack
The layers of regulation that govern this clause, from the FAR prescription through agency-specific supplements and any active deviations.
RFO
RFO Version
Overhauled clause text
The Revolutionary FAR Overhaul publishes a revised version of this clause. See the RFO Version tab for the controlling authority under the RFO model.
FAR
FAR Prescription
36.502
The contracting officer shall insert the clause at 52.236-2, Differing Site Conditions, in solicitations and contracts when a fixed-price construction contract or a fixed-price dismantling, demolition, or removal of improvements contract is contemplated and the contract amount is expected to exceed the simplified acquisition threshold. The contracting officer may insert the clause in solicitations and contracts when a fixed-price construction or a fixed-price contract for dismantling, demolition, or removal of improvements is contemplated and the contract amount is expected to be at or below the simplified acquisition threshold.
Version History
Version history is sourced from the codified eCFR. Changes published only as class deviations or by the Revolutionary FAR Overhaul do not appear here until they are incorporated into the eCFR. For RFO-driven changes see the RFO Version tab and any active deviations cited above.
No version history available from eCFR.
RFO Version
Comparison of the codified eCFR text against the Revolutionary FAR Overhaul revision. Highlights show additions (green) and deletions (red, struck through).
Clause Text
Substantive changes. The RFO version differs materially from the eCFR text.
eCFR (codified)
RFO (implemented)
Unchanged
52.236-2 Differing Site Conditions.
eCFR (codified)
RFO (implemented)
1 added, 1 removed
As prescribed in 36.502, insert the following clause:
As prescribed in 36.101-7(a), insert the following clause:
2 added, 2 removed
Differing Site Conditions (APR 1984)
Differing Site Conditions (Deviation Date)
52 removed
(a)
(a) The Contractor shall promptly, and before the conditions are disturbed, give a written notice to the Contracting Officer of (1) subsurface or latent physical conditions at the site which differ materially from those indicated in this contract, or (2) unknown physical conditions at the site, of an unusual nature, which differ materially from those ordinarily encountered and generally recognized as inhering in work of the character provided for in the contract.
(a)
(a) The Contractor shall promptly, and before the conditions are disturbed, give a written notice to the Contracting Officer of
16 added, 68 removed
(b)
(b) The Contracting Officer shall investigate the site conditions promptly after receiving the notice. If the conditions do materially so differ and cause an increase or decrease in the Contractor's cost of, or the time required for, performing any part of the work under this contract, whether or not changed as a result of the conditions, an equitable adjustment shall be made under this clause and the contract modified in writing accordingly.
(b)
(1) Latent physical conditions or subsurface conditions at the site which differ materially from those indicated in this contract; or
30 added, 44 removed
(c)
(c) No request by the Contractor for an equitable adjustment to the contract under this clause shall be allowed, unless the Contractor has given the written notice required; provided, that the time prescribed in (a) above for giving written notice may be extended by the Contracting Officer.
(c)
(2) Unknown physical conditions at the site, of an unusual nature, which differ materially from those ordinarily encountered and generally recognized as inherent in work of the character provided for in the contract.
1 added, 28 removed
(d)
(d) No request by the Contractor for an equitable adjustment to the contract for differing site conditions shall be allowed if made after final payment under this contract.
(d)
(b)
15 added
(1)
(1)
(1) The Contracting Officer will investigate the site conditions promptly after receiving such a notice.
41 added
(2)
(2)
(2) If the conditions materially so differ and cause an increase or decrease in the Contractor's cost of, or the time required for, performing any part of the work under this contract an equitable adjustment must be made under this clause.
25 added
(c)
(c)
(c) No request for an equitable adjustment to the contract under this clause will be allowed, unless the Contractor has given the written notice required.
25 added
(d)
(d)
(d) No request for an equitable adjustment to the contract for differing site conditions will be allowed if made after final payment under this contract.
15 removed
[48 FR 42478, Sept. 19, 1983, as amended at 60 FR 34761, July 3, 1995]
Prescription
Substantive changes. The RFO prescription differs materially from the eCFR prescription.
eCFR (codified)
RFO (implemented)
Unchanged
52.236-2 Differing Site Conditions.: Prescription
eCFR (codified)
RFO (implemented)
1 added, 88 removed
The contracting officer shall insert the clause at 52.236-2, Differing Site Conditions, in solicitations and contracts when a fixed-price construction contract or a fixed-price dismantling, demolition, or removal of improvements contract is contemplated and the contract amount is expected to exceed the simplified acquisition threshold. The contracting officer may insert the clause in solicitations and contracts when a fixed-price construction or a fixed-price contract for dismantling, demolition, or removal of improvements is contemplated and the contract amount is expected to be at or below the simplified acquisition threshold.
52.236-2
Related Clauses
Referenced by
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