Certification Action Line features questions and answers typical of those appearing in Water Quality Association (WQA) certification examinations. Some answers may not satisfy everyone or every condition.

1. Total dissolved solids in water include:
a) Gases
b) Colloids
c) Minerals
d) Sediment
e) All of the above

2. The major dissolved substances in natural water are comprised of:
a) Iron, manganese, silica and nitrate
b) Calcium, magnesium, sodium, bicarbonate, sulfate and chloride

3. Total solids and dissolved solids are interchangeable terms.
True or False

4. The concentration of dissolved solids in water can be determined by:
a) Specific conductance
b) Weight of residue after evaporation of a known quantity of filtrate
c) The sum of concentrations determined by chemical analysis
d) Specific gravity determinations
e) All of the above

5. The most accurate method of determining total dissolved solids content is:
a) Specific conductance
b) Weight of residue from evaporation of filtrate
c) Sum of concentration determined by chemical analysis

6. The most convenient and rapid method to estimate the total dissolved solids content of water is:
a) Specific conductance
b) Weight of residue from evaporation of filtrate
c) Sum of concentration determined by chemical analysis

7. Specific conductance is related to the degree of electrical resistance of water.
True or False

8. As a general rule for natural drinking waters, the dissolved solids concentration in milligrams per liter (mg/L) can be estimated by multiplying the conductivity measurement in microsiemens (µs) by:
a) 1.00
b) 0.50
c) 2.00
d) 0.65

9. The recommended limit for total dissolved solids (TDS) in drinking water is based mainly on physiological (health) effects.
True or False

10. No municipal water supply may contain more than 500 mg/L of dissolved solids.
True or False