NEW MEXICO WATER OPERATOR CERTIFICATION
EXAM 150 QUESTIONS & CORRECT ANSWERS
LATEST 2026/2027
Maximum Contaminant Level - ANSWER-MCL
Public water system is a system that serves a population of ___ or more regularly -
ANSWER-25
Maximum total chlorine residual ___ mg/l - ANSWER-4
What type of contaminant is Iron - ANSWER-Secondary?
Primary contaminant is sometimes added to water supplies to prevent tooth decay -
ANSWER-Fluoride
The Failure of a public water system to comply with the NM Drinking Water
Regulations must be reported to NMED within ___ hours - ANSWER-48
MCL for Total Trihalomethanes ___ mg/l - ANSWER-0.1
SDWA sampling results must be reported to - ANSWER-New Mexico Enviroment
Department (NMED)
,Ground water systems must sample for inorganic chemicals every ___ years -
ANSWER-3
The SDWA Compliance Cycle for Standardized Monitoring Rule consists of ___
Compliance Periods - ANSWER-3
___ or less than 5% bacteriological samples must be taken every month before a
system is allowed to have TWO positive samples without violating the drinking
water standard? - ANSWER-40
Action level for Lead ___ mg/l - ANSWER-0.015
If Bacteriological retakes are done this month what is the minimum number of
samples that must be turned in next month? - ANSWER-5
if a 3-log removal is required for Giardia Lamblia what percentage of organisms
can survive and still meet requirements - ANSWER-0.1
Primary Inorganic Contaminant poses an immediate health risk - ANSWER-
Nitrates
The Presence of Nitrates in the bloodstream that reduces oxygen uptake that gives
the skin a blue tint - ANSWER-Blue Baby Syndrome
Primary Contaminant that shields harmful bacteria from disinfection processes -
ANSWER-Turbidity
Device used to measure NTU's - ANSWER-Nephelometer
, Turbidity is Measured with - ANSWER-Turbidimeter or Nephelometer
Chemical sampling results be kept ___ years - ANSWER-10
Bacteriological sampling results be kept ___ years - ANSWER-5
Microorganisms whose presence in water indicates probable presence of
pathogens. - ANSWER-Indicator organism
White powder used to neutralize chlorine - ANSWER-Sodium Thiosulphate
To insure the water being sampled is from the main and not the customers
plumbling - ANSWER-Flush line
Number is used to determine how many Bac-t samples must be taken - ANSWER-
People served
Minimum number of Bac-T samples required each month? - ANSWER-1
Anytime the MCL is exceeded and fecal coliform positive results come back from
any of the samples - ANSWER-Non-acute violation
If retakes are required this month what is the minimum number of samples
required next month - ANSWER-5
EXAM 150 QUESTIONS & CORRECT ANSWERS
LATEST 2026/2027
Maximum Contaminant Level - ANSWER-MCL
Public water system is a system that serves a population of ___ or more regularly -
ANSWER-25
Maximum total chlorine residual ___ mg/l - ANSWER-4
What type of contaminant is Iron - ANSWER-Secondary?
Primary contaminant is sometimes added to water supplies to prevent tooth decay -
ANSWER-Fluoride
The Failure of a public water system to comply with the NM Drinking Water
Regulations must be reported to NMED within ___ hours - ANSWER-48
MCL for Total Trihalomethanes ___ mg/l - ANSWER-0.1
SDWA sampling results must be reported to - ANSWER-New Mexico Enviroment
Department (NMED)
,Ground water systems must sample for inorganic chemicals every ___ years -
ANSWER-3
The SDWA Compliance Cycle for Standardized Monitoring Rule consists of ___
Compliance Periods - ANSWER-3
___ or less than 5% bacteriological samples must be taken every month before a
system is allowed to have TWO positive samples without violating the drinking
water standard? - ANSWER-40
Action level for Lead ___ mg/l - ANSWER-0.015
If Bacteriological retakes are done this month what is the minimum number of
samples that must be turned in next month? - ANSWER-5
if a 3-log removal is required for Giardia Lamblia what percentage of organisms
can survive and still meet requirements - ANSWER-0.1
Primary Inorganic Contaminant poses an immediate health risk - ANSWER-
Nitrates
The Presence of Nitrates in the bloodstream that reduces oxygen uptake that gives
the skin a blue tint - ANSWER-Blue Baby Syndrome
Primary Contaminant that shields harmful bacteria from disinfection processes -
ANSWER-Turbidity
Device used to measure NTU's - ANSWER-Nephelometer
, Turbidity is Measured with - ANSWER-Turbidimeter or Nephelometer
Chemical sampling results be kept ___ years - ANSWER-10
Bacteriological sampling results be kept ___ years - ANSWER-5
Microorganisms whose presence in water indicates probable presence of
pathogens. - ANSWER-Indicator organism
White powder used to neutralize chlorine - ANSWER-Sodium Thiosulphate
To insure the water being sampled is from the main and not the customers
plumbling - ANSWER-Flush line
Number is used to determine how many Bac-t samples must be taken - ANSWER-
People served
Minimum number of Bac-T samples required each month? - ANSWER-1
Anytime the MCL is exceeded and fecal coliform positive results come back from
any of the samples - ANSWER-Non-acute violation
If retakes are required this month what is the minimum number of samples
required next month - ANSWER-5
