State and Federal agencies require scheduled Mechanical Integrity Tests (MIT) of wells used for the underground disposal of hazardous materials. The corrosive nature of the materials being injected dictates that high nickel wireline (MP35) and corrosion resistant gauges be used for these downhole tests. These special wireline units and gauges command premium rental charges. However, the MIT Test can be conducted with surface measurements without the expense and risk of introducing tools and wireline into the well bore. The surface gauge must be suitable for use in a corrosive environment and of sufficient accuracy and repeatability to meet the standards of the state and federal regulatory authorities. The SPIDR® system with its dual quartz pressure transducer and corrosion resistant construction meets or exceeds all requirements for MIT testing.