Texas Class D Water License Questions
and Answers| Latest Update
Dosage is the amount of chemical applied in mg/L or ppm. Demand is the amount of chemical
used up by reducing agents. What is the amount of chemical remaining after reacting with
demand/ residual
DOSAGE = DEMAND + residual
What is the minimum disinfection residual in the distribution system for free chlorine? 0.2
mg/L
What is the minimum disinfection residual in the distribution system for chloramine? 0.5
mg/L
What is the maximum free chlorine or chloramine residual for all community and non-transient,
non community water systems? 4 mg/L
DPD (diethyl-p-phenylene-diamine) measures the chlorine residual in water in mg/L. The DPD
and chlorine reaction turns the water a pink to ? color. red
? and water make two acids: hydrocloric (HCL) and hypochlorous (HOCL), the disinfectant.
chlorine
,The TCEQ allows no more than ? mg/L of chlorine dioxide in the distribution system. 0.8
Ozone is made of ? oxygen atoms instead of two 3
95% of all distribution residual readings must be above the minimum for how many consecutive
monthly periods? 2
Waterborne or water-carried pathogens live and grow in the intestines of infected? people
Every water sample is tested for waterborne diseases false
Water samples are tested for ? that indicate fecal contamination. microorganisms
The total coliform group of ? are the indicators of fecal contamination? bacteria
If used in public drinking water, bleach must be NSF approved. What does NSF stand for?
National Sanitation Foundation
Sodium Thiosulfate is put into bacteriological sample bottles to ? the water. neutralize
Before taking a bacteriological sample you must ? the service line. flush
, The monthly bacteriological sample should be marked? distribution
In order to not have your samples rejected they should be in the lab before how many hours?
30
You must notify the public about acute violations within how many hours? by radio and
television using the words "Minor Health Concern." 24
In the event of low distribution pressure (below 20 psi), water outages, repeated unacceptable
microbiological samples , or failure to maintain adequate chlorine residuals, special precautions
must be instituted by the? water system
In Texas, all public water systems must have ? facilities. chlorination
Chlorination is the most important process in the production of ? water. potable
Calcium hypochlorite will cause explosions or fires if it contacts ? material. organic
At room temperature, chlorine gas is greenish-yellow, has a pungent odor is ? times heavier than
air. 2 1/2
The maximum sustained gas withdrawal rate from 150-lb, cylinders (vacuum transmissions) is ?
lbs(s)./day per degree F. 1
and Answers| Latest Update
Dosage is the amount of chemical applied in mg/L or ppm. Demand is the amount of chemical
used up by reducing agents. What is the amount of chemical remaining after reacting with
demand/ residual
DOSAGE = DEMAND + residual
What is the minimum disinfection residual in the distribution system for free chlorine? 0.2
mg/L
What is the minimum disinfection residual in the distribution system for chloramine? 0.5
mg/L
What is the maximum free chlorine or chloramine residual for all community and non-transient,
non community water systems? 4 mg/L
DPD (diethyl-p-phenylene-diamine) measures the chlorine residual in water in mg/L. The DPD
and chlorine reaction turns the water a pink to ? color. red
? and water make two acids: hydrocloric (HCL) and hypochlorous (HOCL), the disinfectant.
chlorine
,The TCEQ allows no more than ? mg/L of chlorine dioxide in the distribution system. 0.8
Ozone is made of ? oxygen atoms instead of two 3
95% of all distribution residual readings must be above the minimum for how many consecutive
monthly periods? 2
Waterborne or water-carried pathogens live and grow in the intestines of infected? people
Every water sample is tested for waterborne diseases false
Water samples are tested for ? that indicate fecal contamination. microorganisms
The total coliform group of ? are the indicators of fecal contamination? bacteria
If used in public drinking water, bleach must be NSF approved. What does NSF stand for?
National Sanitation Foundation
Sodium Thiosulfate is put into bacteriological sample bottles to ? the water. neutralize
Before taking a bacteriological sample you must ? the service line. flush
, The monthly bacteriological sample should be marked? distribution
In order to not have your samples rejected they should be in the lab before how many hours?
30
You must notify the public about acute violations within how many hours? by radio and
television using the words "Minor Health Concern." 24
In the event of low distribution pressure (below 20 psi), water outages, repeated unacceptable
microbiological samples , or failure to maintain adequate chlorine residuals, special precautions
must be instituted by the? water system
In Texas, all public water systems must have ? facilities. chlorination
Chlorination is the most important process in the production of ? water. potable
Calcium hypochlorite will cause explosions or fires if it contacts ? material. organic
At room temperature, chlorine gas is greenish-yellow, has a pungent odor is ? times heavier than
air. 2 1/2
The maximum sustained gas withdrawal rate from 150-lb, cylinders (vacuum transmissions) is ?
lbs(s)./day per degree F. 1
