Water Quality, Testing, and Treatment
What the exam tests
This domain tests contaminant knowledge, correct sampling, New Jersey standards, and treatment selection. The Private Well Testing Act (PWTA) is a frequent source of questions because it sets a real-estate testing trigger and a defined parameter list.
Core content
- PWTA testing applies to sale or lease of property with a private well; a certified lab tests for total coliform, E. coli, nitrate, pH, arsenic, lead, mercury, manganese, iron, VOCs, gross alpha, radium-226/228, and uranium, with county-specific additions where required.
- New Jersey's arsenic MCL is 5 µg/L, stricter than the federal 10 µg/L. Lead action level is 15 µg/L; nitrate MCL is 10 mg/L as nitrogen. Iron and manganese are secondary contaminants (300 and 50 µg/L).
- Sampling: use the lab's sterile bottle, remove the aerator, purge, and avoid flame or contamination. Bacteria samples must be chilled and delivered within holding time. Sample the raw well before treatment unless the protocol says otherwise.
- Treatment: sediment filtration for turbidity; activated carbon for VOCs and taste/odor; ion exchange softening for hardness; oxidation plus filtration for iron/manganese; adsorption media for arsenic; reverse osmosis for many dissolved ions; UV for bacteria.
Worked example
A PWTA report shows arsenic 12 µg/L, iron 0.8 mg/L, and total coliform absent. Because arsenic exceeds 5 µg/L, the well fails the PWTA standard. Do not install a water softener and call it treatment. Select an arsenic adsorption unit sized for the household flow and backwash needs, confirm the pH and competing ions (silica, phosphate, iron) are compatible, and retest treated water at a certified lab.
Traps
Taking a bacteria sample from a chlorinated line or after the softener. Confusing a secondary aesthetic limit with an MCL. Treating only at one tap when the contaminant is inhaled or absorbed in the shower. Reporting a lab result without the sampling point and date.