CWEA Grade I Laboratory Analyst (Water
Quality Testing and Analysis) – EXAM
STUDY GUIDE 2026/2027 COMPLETE
QUESTIONS WITH VERIFIED CORRECT
ANSWERS || 100% GUARANTEED PASS
Sample seals - ANSWER Should include sample number that is identical to sample label,
collector's name, date and time of sampling. Attach so it must be broken to open sample
container.
Sample temperature adjustment for BOD - ANSWER Bring samples to 20 +/- 3 C.
Samples that require nitrification inhibition - ANSWER Biologically treated effluents, samples
seeded with biologically treated effluents, and river water.
Samples with Hydrogen peroxide with DO - ANSWER Mix samples vigorously in open
containers for sufficient time to allow hydrogen peroxide levels to dissipate.
Sampling protocol for acidity - ANSWER Plastic, Borosilicate glass, fluoropolymer, cool to </=
6 C.
Sampling protocol for alkalinity - ANSWER Plastic, glass, fluoropolymer, cool to </= 6 C.
Sampling protocol for BOD - ANSWER Plastic, glass, fluoropolymer, cool to </= 6 C
,Sampling protocol for chloride - ANSWER Plastic, glass, fluoropolymer, no preservative
required
Sampling protocol for chloride includes - ANSWER Glass or plastic container with no
preservative
Sampling protocol for chlorine residual - ANSWER Plastic, glass, fluoropolymer, analyze
immediately (no preservative since chlorine changes rapidly)
Sampling protocol for COD - ANSWER Plastic, glass, fluoropolymer, analyze ASAP, or add
H2SO4 to pH <2, cool to </= 6 C
Sampling protocol for Color - ANSWER Plastic, glass, cool </= 6 C
Sealing BOD bottles - ANSWER Fill each bottle enough to where insertion of stopper leaves
no bubbles in bottle. Mix sample by turning bottle manually several times
Seed suspension for BOD analysis - ANSWER Preferred seeds include supernatant from
settled domestic wastewater, effluent from primary clarifiers, diluted mixed liquor from an
aeration basin, disinfected effluent, or receiving water from below the point of discharge
Short term storage of pH electrodes - ANSWER pH 4 buffer
Standard phenylarsine oxide solution (PAO) - ANSWER Should be handled with caution
because its is a severe poison
Standard units for color - ANSWER One unit= color resulting from 1 mg of platinum/L
,Sterilization of agar - ANSWER 121 C for 15 min
Temperature conductivity should be read at - ANSWER 25 degrees Celcius
Temperature instruments - ANSWER Mercury filled glass thermometers with scale markings
at a minimum of every 0.1 C
The hardness determination by EDTA titration measures - ANSWER Calcium and magnesium
The indicator for the hardness determination is - ANSWER eriochrome Black T
The phenolphthalein alkalinity of a water sample is zero if - ANSWER The pH is greater than
8.3
The sample receiving log must record - ANSWER time and date sampled, sample collector,
nature of sample, analyses to be performed, preservatives, condition of sample and sample
recipient
Titrant used for hardness - ANSWER 0.01 M EDTA solutions
Total coliform group - ANSWER All of the aerobic and facultative anaerobic, gram negative,
nonspore-forming, rod shaped bacteria that ferment lactose in 24-48 hours at 35 degrees C
Total Dissolved Solids - ANSWER A well mixed sample is filtered through standard glass fiber
filter and filtrate is evaporated to dryness in weighed dish and dried to constant weight at 180
degrees C
, Total Solids - ANSWER Well mixed sample is evaporated in a weighed dish and dried to
constant weight in an oven at 103-105 degrees C
Total Suspended Solids - ANSWER A well mixed sample filtered through weighed standard
glass fiber filter and residue retained is dried to constant weight at 103-105 degrees C
True color - ANSWER Color from dissolved substances, determine using sample treated to
remove turbidity
Turbidity if measured with - ANSWER Nephelometer
Turbidity measurement is used to - ANSWER Measure the operational effectiveness of
filtration in potable and reclaimed water treatment
Units of conductivity - ANSWER micromhos/cm
Units of hardness - ANSWER mg/L CaCO3
Units of turbidity - ANSWER Nephelometric Turbidity Units (NTU)
Valid data of BOD analysis - ANSWER - Minimum depletion of 2.0 mg/L DO
- Residual DO of 1.0 mg/L
Viscosity - ANSWER A liquids ability to resist flow, higher the viscosity the lower the flow
Quality Testing and Analysis) – EXAM
STUDY GUIDE 2026/2027 COMPLETE
QUESTIONS WITH VERIFIED CORRECT
ANSWERS || 100% GUARANTEED PASS
Sample seals - ANSWER Should include sample number that is identical to sample label,
collector's name, date and time of sampling. Attach so it must be broken to open sample
container.
Sample temperature adjustment for BOD - ANSWER Bring samples to 20 +/- 3 C.
Samples that require nitrification inhibition - ANSWER Biologically treated effluents, samples
seeded with biologically treated effluents, and river water.
Samples with Hydrogen peroxide with DO - ANSWER Mix samples vigorously in open
containers for sufficient time to allow hydrogen peroxide levels to dissipate.
Sampling protocol for acidity - ANSWER Plastic, Borosilicate glass, fluoropolymer, cool to </=
6 C.
Sampling protocol for alkalinity - ANSWER Plastic, glass, fluoropolymer, cool to </= 6 C.
Sampling protocol for BOD - ANSWER Plastic, glass, fluoropolymer, cool to </= 6 C
,Sampling protocol for chloride - ANSWER Plastic, glass, fluoropolymer, no preservative
required
Sampling protocol for chloride includes - ANSWER Glass or plastic container with no
preservative
Sampling protocol for chlorine residual - ANSWER Plastic, glass, fluoropolymer, analyze
immediately (no preservative since chlorine changes rapidly)
Sampling protocol for COD - ANSWER Plastic, glass, fluoropolymer, analyze ASAP, or add
H2SO4 to pH <2, cool to </= 6 C
Sampling protocol for Color - ANSWER Plastic, glass, cool </= 6 C
Sealing BOD bottles - ANSWER Fill each bottle enough to where insertion of stopper leaves
no bubbles in bottle. Mix sample by turning bottle manually several times
Seed suspension for BOD analysis - ANSWER Preferred seeds include supernatant from
settled domestic wastewater, effluent from primary clarifiers, diluted mixed liquor from an
aeration basin, disinfected effluent, or receiving water from below the point of discharge
Short term storage of pH electrodes - ANSWER pH 4 buffer
Standard phenylarsine oxide solution (PAO) - ANSWER Should be handled with caution
because its is a severe poison
Standard units for color - ANSWER One unit= color resulting from 1 mg of platinum/L
,Sterilization of agar - ANSWER 121 C for 15 min
Temperature conductivity should be read at - ANSWER 25 degrees Celcius
Temperature instruments - ANSWER Mercury filled glass thermometers with scale markings
at a minimum of every 0.1 C
The hardness determination by EDTA titration measures - ANSWER Calcium and magnesium
The indicator for the hardness determination is - ANSWER eriochrome Black T
The phenolphthalein alkalinity of a water sample is zero if - ANSWER The pH is greater than
8.3
The sample receiving log must record - ANSWER time and date sampled, sample collector,
nature of sample, analyses to be performed, preservatives, condition of sample and sample
recipient
Titrant used for hardness - ANSWER 0.01 M EDTA solutions
Total coliform group - ANSWER All of the aerobic and facultative anaerobic, gram negative,
nonspore-forming, rod shaped bacteria that ferment lactose in 24-48 hours at 35 degrees C
Total Dissolved Solids - ANSWER A well mixed sample is filtered through standard glass fiber
filter and filtrate is evaporated to dryness in weighed dish and dried to constant weight at 180
degrees C
, Total Solids - ANSWER Well mixed sample is evaporated in a weighed dish and dried to
constant weight in an oven at 103-105 degrees C
Total Suspended Solids - ANSWER A well mixed sample filtered through weighed standard
glass fiber filter and residue retained is dried to constant weight at 103-105 degrees C
True color - ANSWER Color from dissolved substances, determine using sample treated to
remove turbidity
Turbidity if measured with - ANSWER Nephelometer
Turbidity measurement is used to - ANSWER Measure the operational effectiveness of
filtration in potable and reclaimed water treatment
Units of conductivity - ANSWER micromhos/cm
Units of hardness - ANSWER mg/L CaCO3
Units of turbidity - ANSWER Nephelometric Turbidity Units (NTU)
Valid data of BOD analysis - ANSWER - Minimum depletion of 2.0 mg/L DO
- Residual DO of 1.0 mg/L
Viscosity - ANSWER A liquids ability to resist flow, higher the viscosity the lower the flow
