E. coli (Potable water) – Detection

Laboratory Fee Schedule

Procedure: MZZ0441A

Synonym(s): Total coliform, Drinking Water Test
Requisition Form G-19
Test Description Detects the presence of E. coli and total coliform bacteria in potable water.
Pre-Approval Needed N/A
Supplemental Information Required N/A
Supplemental Form(s) N/A  
Performed on Specimens from (sources) Water
Sample/Specimen Type for Testing
  • Water (potable; non-silo dairy) samples
Minimum Volume/Size Required
  • 105 mL
Storage/Preservation Prior to Shipping
  • Place sample in water-tight, wide-mouthed container with a capacity of at least 120 mL (4 oz).
  • Sodium thiosulfate (100mg/L) must be added to containers before sterilization (0.1 mL of 10% sodium thiosulfate solution, appropriate tablet, or powder).
  • Potable water samples must be tested within 30 hours of collection.
  • Non-silo dairy water samples must be.
    • tested within 6 hours of collection if not refrigerated (temperature control not required); or
    • maintained at 0.0° to 4.5°C and shipment must include temperature control.
Transport Medium N/A
Specimen Labeling Sample Identification must match submission form.
Shipping and Specimen Handling Requirements
  • If shipped, samples must be shipped for overnight delivery.
  • Potable water samples must be tested within 30 hours of collection.
  • Colilert® test
Turn-around Time 1 Day
  • Can detect E. coli and/or total coliform bacteria at a sensitivity of 1 CFU/100 mL.
  • In samples with excessive chlorine, a blue flash may be seen when adding Colilert® or Colilert®-18. If this occurs, sample will be considered invalid, and testing will be discontinued.
Causes for Rejection Insufficient specimen, improperly stored and/or failure to meet shipping guidelines.
Additional Information N/A