1.5″ diameter Float Style Interface Probe (100′)

Manufacturer: Geotech
Order / Quote

The Keck Interface Probe is a portable instrument capable of accurately measuring water and hydrocarbon levels and hydrocarbon layer thickness in monitoring wells. The probe consists of a stainless steel and Teflon® probe attached to a reel-mounted, Tefzel* coated engineer's tape. The engineer's tape comes in standard or metric graduations and is accurate to 1/100 of a foot. The probe has a float which detects hydrocarbon levels and a pair of stainless steel contacts for sensing conductive fluids.

The probe has an audible buzzer signal and a visible light which are activated when the instrument reaches water or product. The probe features an auto shutoff circuit to prevent battery discharge. This auto shutoff circuit allows the instrument 10 minutes of continuous operation before the unit shuts off.

When the Keck Interface Probe is lowered down a well and contacts any fluid with a specific gravity of .60 or greater, the float will activate the visible and audible signals. If the fluid is non-conductive, the light will be red and a solid tone will sound. If the fluid is water or other conductive fluid, the conductive contacts will cause the light to turn green and the tone will oscillate. If the probe is lowered through the water layer to a non-conductive layer (such as DNAPL) the tone will change and the light will return to red.


  • Material: Stainless steel & Teflon®
  • Weight: 19.75 oz. (560 g)
  • Diameter: 1.5" (3.8 cm)
  • Length: 8.9" (22.6 cm)
  • Conductivity threshold (detects water at) : >6.7 MS
  • Minimum detectable hydrocarbon: .01 foot


  • Material: Tefzel coated stainless steel
  • Length/Weight: 100 ft. / 30 meters = 9 lbs
  • Accuracy
    • 100th of a foot/100’
    • Per Federal Specification GGG-T-106E


  • Material: Polypropylene & aluminum
  • Size: 13” H x 11” W x 7” D


  • Battery: 9 volt alkaline
  • Self shut – off time: 10 minutes
  • Output tone: 500 Hz
  • Modulation (water detected): 3.5 H
  • Operating temperature range: 32 – 140° F (0 – 60° C)
  • Storage temperature range: -40 – 158° F (-40 – 70° C)
  • Response time: <10 milliseconds