The pH of halogenated solvents varies according to the nature of stabilizers in the particular solvent. Solvents with alkaline stabilizers (amine-types) generally have pHs in the 7 to 11 range, whereas solvents containing neutral stabilizers (epoxide-types) generally have pHs in the 5 to 7 range.

Virgin and reclaimed solvents should have pHs within these ranges, dependent upon the claimed method of stabilization. These values should be within the accepted limits as proposed by the producers of the original virgin solvent.

A lowering of pH from the above values, on receipt or use, is cause for concern. In this event, solvents having epoxide stabilizers should be tested for acid acceptance; solvent having alkaline stabilizers should be tested for alkalinity.