The head of a Federal agency shall make every reasonable effort to acquire expeditiously real property by negotiation.

Real property shall be appraised before the initiation of negotiations, and the owner or his designated representative shall be given an opportunity to accompany the appraiser during his inspection of the property, except that the head of the lead agency may prescribe a procedure to waive the appraisal in cases involving the acquisition by sale or donation of property with a low fair market value.

Before the initiation of negotiations for real property, the head of the Federal agency concerned shall establish an amount which he believes to be just compensation therefor and shall make a prompt offer to acquire the property for the full amount so established. In no event shall such amount be less than the agency’s approved appraisal of the fair market value of such property. Any decrease or increase in the fair market value of real property prior to the date of valuation caused by the public improvement for which such property is acquired, or by the likelihood that the property would be acquired for such improvement, other than that due to physical deterioration within the reasonable control of the owner, will be disregarded in determining the compensation for the property. The head of the Federal agency concerned shall provide the owner of real property to be acquired with a written statement of, and summary of the basis for, the amount he established as just compensation. Where appropriate the just compensation for the real property acquired and for damages to remaining real property shall be separately stated.