NGWA General Ground Water Replenishing system
Groundwater, Water Treatment, Capacity
Comprehensive Resource To Help You Ace 2026-2027 Exams
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!! Current Update!!
1. What is the operating capacity of the Groundwater Basin? - Correct
Answer: 500,000 acre-feet
2. How much water is in the OC Groundwater Basin? - Correct Answer:
Nearly 163 billion gallons
3. 163 billion gallons of water is how many olympic sized swimming pools? -
Correct Answer: 247,000 or more than a quarter million
4. When was the Orange County Water District (OCWD) formed and how? -
Correct Answer: In 1933 by an act of the California State Legislature.
5. What percentage of drinking water does the Groundwater Basin supply for
how many people? - Correct Answer: Approximately 85% of drinking
water for 2.5 million people.
,6. What are the main recharge sources for the Groundwater Basin? -
Correct Answer: Santa Ana River flows, local rainfall, GWRS-purified
recycled water, and imported water.
7. What recognition did OCWD receive in 2006? - Correct Answer:
Designated a Historical Civil Engineering Landmark.
8. What is the average annual rainfall in the OCWD area? - Correct
Answer: 14 inches, which is less than half the US average.
9. What world record does OCWD hold? - Correct Answer: The most
wastewater recycled to drinking water in a 24-hour period.
10.What is the purpose of the Groundwater Replenishment System (GWRS)? -
Correct Answer: To recycle treated wastewater to create high-quality
drinking water.
11.What is the total capacity of the GWRS? - Correct Answer: 130 million
gallons per day (MGD).
12.When did the GWRS come online? - Correct Answer: In 2008, with
expansions in 2015 and 2023.
13.What is the significance of the GWRS's closed loop system? - Correct
Answer: It recycles 100% of reclaimable flows from OC San Plants 1 & 2.
,14.What were the construction costs for the GWRS? - Correct Answer:
Total costs exceeded $900 million.
15.How does the energy use of GWRS compare to imported water? -
Correct Answer: GWRS uses half the energy compared to imported water.
16.What is the role of OC San in the GWRS? - Correct Answer: Provides
100% of the reclaimable secondary-treated wastewater for GWRS.
17.What is the treatment step 1 in the GWRS process? - Correct Answer:
Microfiltration (MF), which removes suspended solids, protozoa, bacteria,
and some viruses.
18.How many MF cells are there in the GWRS? - Correct Answer: There are
48 MF cells.
19.What is the pore size of the MF membranes? - Correct Answer:
Approximately 1/300th the diameter of a human hair.
20.What is the optimal feed water turbidity for the MF process? - Correct
Answer: 3-5 NTU (Nephelometric Turbidity Units).
21.What is the feed pressure range for the MF process? - Correct Answer:
3-12 PSI (Pounds per Square Inch).
, 22.What is the significance of the gravity-based piping in the GWRS? -
Correct Answer: It minimizes energy use by directing water downhill from
OC San to GWRS.
23.What is the byproduct of the GWRS process that is not recycled? -
Correct Answer: Brine-heavy flows from high-salinity industrial wastewater
(IEBL/SARI).
24.What is the main benefit of the GWRS project? - Correct Answer:
Drought resilience, reduced ocean discharge, and energy efficiency.
25.How many awards has the GWRS facility received? - Correct Answer:
Over 100 awards for innovation, engineering, and sustainability.
26.What is the total amount of water received from OC San for the GWRS? -
Correct Answer: 170 million gallons per day (MGD).
27.What is the role of the Steve Anderson Lift Station in the GWRS? -
Correct Answer: It maximizes flows to GWRS by directing water from Plant 2
to Plant 1.
28.What is the maintenance schedule for microfiltration (MF) systems? -
Correct Answer: Backwash every 22 minutes and full chemical cleaning
every 21 days.
Groundwater, Water Treatment, Capacity
Comprehensive Resource To Help You Ace 2026-2027 Exams
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!! Current Update!!
1. What is the operating capacity of the Groundwater Basin? - Correct
Answer: 500,000 acre-feet
2. How much water is in the OC Groundwater Basin? - Correct Answer:
Nearly 163 billion gallons
3. 163 billion gallons of water is how many olympic sized swimming pools? -
Correct Answer: 247,000 or more than a quarter million
4. When was the Orange County Water District (OCWD) formed and how? -
Correct Answer: In 1933 by an act of the California State Legislature.
5. What percentage of drinking water does the Groundwater Basin supply for
how many people? - Correct Answer: Approximately 85% of drinking
water for 2.5 million people.
,6. What are the main recharge sources for the Groundwater Basin? -
Correct Answer: Santa Ana River flows, local rainfall, GWRS-purified
recycled water, and imported water.
7. What recognition did OCWD receive in 2006? - Correct Answer:
Designated a Historical Civil Engineering Landmark.
8. What is the average annual rainfall in the OCWD area? - Correct
Answer: 14 inches, which is less than half the US average.
9. What world record does OCWD hold? - Correct Answer: The most
wastewater recycled to drinking water in a 24-hour period.
10.What is the purpose of the Groundwater Replenishment System (GWRS)? -
Correct Answer: To recycle treated wastewater to create high-quality
drinking water.
11.What is the total capacity of the GWRS? - Correct Answer: 130 million
gallons per day (MGD).
12.When did the GWRS come online? - Correct Answer: In 2008, with
expansions in 2015 and 2023.
13.What is the significance of the GWRS's closed loop system? - Correct
Answer: It recycles 100% of reclaimable flows from OC San Plants 1 & 2.
,14.What were the construction costs for the GWRS? - Correct Answer:
Total costs exceeded $900 million.
15.How does the energy use of GWRS compare to imported water? -
Correct Answer: GWRS uses half the energy compared to imported water.
16.What is the role of OC San in the GWRS? - Correct Answer: Provides
100% of the reclaimable secondary-treated wastewater for GWRS.
17.What is the treatment step 1 in the GWRS process? - Correct Answer:
Microfiltration (MF), which removes suspended solids, protozoa, bacteria,
and some viruses.
18.How many MF cells are there in the GWRS? - Correct Answer: There are
48 MF cells.
19.What is the pore size of the MF membranes? - Correct Answer:
Approximately 1/300th the diameter of a human hair.
20.What is the optimal feed water turbidity for the MF process? - Correct
Answer: 3-5 NTU (Nephelometric Turbidity Units).
21.What is the feed pressure range for the MF process? - Correct Answer:
3-12 PSI (Pounds per Square Inch).
, 22.What is the significance of the gravity-based piping in the GWRS? -
Correct Answer: It minimizes energy use by directing water downhill from
OC San to GWRS.
23.What is the byproduct of the GWRS process that is not recycled? -
Correct Answer: Brine-heavy flows from high-salinity industrial wastewater
(IEBL/SARI).
24.What is the main benefit of the GWRS project? - Correct Answer:
Drought resilience, reduced ocean discharge, and energy efficiency.
25.How many awards has the GWRS facility received? - Correct Answer:
Over 100 awards for innovation, engineering, and sustainability.
26.What is the total amount of water received from OC San for the GWRS? -
Correct Answer: 170 million gallons per day (MGD).
27.What is the role of the Steve Anderson Lift Station in the GWRS? -
Correct Answer: It maximizes flows to GWRS by directing water from Plant 2
to Plant 1.
28.What is the maintenance schedule for microfiltration (MF) systems? -
Correct Answer: Backwash every 22 minutes and full chemical cleaning
every 21 days.
