The Sewer Inspector and other duly authorized employees or representatives of the municipality and of any contracting municipality, bearing proper credentials and identification, shall be permitted to enter all properties for the purposes of inspection, observation, measurement, sampling and testing in accordance with the provisions of the law, all the foregoing not to be carried out beyond a point having a direct bearing on the kind and source of discharge to the sewers or waterways or facilities for waste treatment. The foregoing shall also apply for the purposes of but not limited to inspection, observation, measurement, sampling, repair and maintenance of any portion of the sewage works lying within any duly negotiated easement between the municipality and any private property owner. New York State Department of Environmental Conservation and United States Environmental Protection Agency officials shall have the same powers and authority of inspection enjoyed by the Sewer Inspector or other duly authorized employees or representatives of the municipality as pertain to commercial or industrial discharges to the system.