https://www.epa.gov/hw-sw846/sw-846-test-method-9040c-ph-electrometric-measurement
SW-846 Test Method 9040C: pH Electrometric Measurement | US EPA
Jul 22, 2025 - procedure to measure the pH of aqueous wastes and those multiphase wastes where the aqueous phase constitutes at least 20% of the total volume of the waste
test methodswphmeasurementus