CWS Point-of-Use vs Point-of-Entry Systems 2 — Questions and Answers
Question 1: A homeowner wants to protect only the water used for drinking and cooking. Which system type is most appropriate?
- Whole-house softener
- Point-of-use system (Correct answer)
- Point-of-entry system
- Backwash filter on main line
Correct answer: Point-of-use system
Point-of-use systems treat water at a single outlet, making them ideal when only drinking and cooking water requires treatment.
Question 2: Which POE system type is most commonly used to remove iron and manganese from a private well supply?
- Reverse osmosis
- Oxidizing filter with backwash (Correct answer)
- Activated carbon block
- UV lamp at the kitchen tap
Correct answer: Oxidizing filter with backwash
Oxidizing backwash filters (e.g., greensand or Birm) oxidize and filter iron and manganese from the entire water supply at the entry point.
Question 3: A POU reverse osmosis unit produces permeate at a typical recovery rate of:
- 70–90%
- 50–65%
- 15–35% (Correct answer)
- 1–5%
Correct answer: 15–35%
Most residential POU RO systems recover 15–35% of feed water as product water, rejecting the rest as concentrate drain water.
Question 4: When a POE softener is installed before a water heater, the primary benefit is:
- Removing chlorine taste from drinking water
- Preventing scale buildup inside the water heater and pipes (Correct answer)
- Reducing nitrate levels in all fixtures
- Eliminating the need for a POU filter
Correct answer: Preventing scale buildup inside the water heater and pipes
Softening hard water before it enters the water heater prevents calcium carbonate scale from depositing inside the tank and heating elements.
Question 5: A POU ultraviolet system installed under a kitchen sink protects against:
- Lead leached from pipes throughout the house
- Hardness scaling at the kitchen faucet only
- Microbial contamination in the water dispensed at that point (Correct answer)
- Chlorine in both hot and cold lines
Correct answer: Microbial contamination in the water dispensed at that point
A POU UV unit disinfects water at the specific outlet where it is installed, inactivating bacteria and viruses in that stream only.
Question 6: Which factor most directly determines whether a POE or POU approach is more cost-effective for a household with only one aesthetic concern (taste/odor) at the kitchen tap?
- The pH of the source water
- The number of bathrooms in the home
- Treating a single outlet vs. the whole house for a localized problem (Correct answer)
- The hardness level of the water
Correct answer: Treating a single outlet vs. the whole house for a localized problem
When only one outlet has an aesthetic concern, a POU device is far less expensive to purchase, install, and maintain than a whole-house POE system.
Question 7: A POE acid neutralizer raises pH by:
- Adding sodium hydroxide solution via a chemical feed pump at each tap
- Passing water through a bed of calcite or corosex media that dissolves into the water (Correct answer)
- Running water through a cation exchange resin
- Injecting carbon dioxide downstream of the pressure tank
Correct answer: Passing water through a bed of calcite or corosex media that dissolves into the water
Calcite (calcium carbonate) and corosex (magnesium oxide) neutralizer media dissolve slightly into acidic water, raising pH throughout the home.
CWS Point-of-Use vs Point-of-Entry Systems 2
A homeowner wants to protect only the water used for drinking and cooking.
Which system type is most appropriate?