HIC Water Quality & Sampling 2

Question 1

What is the maximum contaminant level (MCL) for total coliform bacteria in public water systems under the Revised Total Coliform Rule?

Accepted Answer

Zero — no coliform-positive samples allowed in systems with <1,000 monthly samples

Answer

The Revised Total Coliform Rule sets an MCL violation when coliform-positive samples exceed 5% in a month for large systems, but for systems with fewer than 40 monthly samples, any positive triggers an E. coli follow-up.

Question 2

Which sampling technique is required when collecting a bacteriological water sample from a tap to ensure accurate results?

Accepted Answer

Flame or sanitize the tap, run cold water 2-3 minutes, then collect without touching the faucet interior

Answer

Sanitizing the tap and flushing 2-3 minutes removes biofilm and stagnant water, yielding a representative distribution system sample.

Question 3

A health inspector finds turbidity in a filtered public water system exceeds 1 NTU in more than 5% of measurements in a month. What does this indicate?

Accepted Answer

A treatment technique violation under the Surface Water Treatment Rule

Answer

Exceeding 1 NTU in more than 5% of monthly measurements constitutes a treatment technique violation under the Surface Water Treatment Rule.

Question 4

What holding time and temperature are required for bacteriological water samples collected for total coliform analysis?

Accepted Answer

24 hours at 10°C or below

Answer

Standard Methods specify a 24-hour maximum holding time at ≤10°C for total coliform samples to preserve sample integrity.

Question 5

Under the Lead and Copper Rule, first-draw lead samples must be collected after water has been stagnant for at least how long?

Accepted Answer

6 hours

Answer

The Lead and Copper Rule requires a minimum 6-hour stagnation period before first-draw sampling to capture lead leaching from plumbing.

(HIC) Health Inspector Certification Practice Test

(HIC) Health Inspector Certification Practice Test

HIC Water Quality & Sampling 2