Chapter 6 Quiz: Your Home's Water Supply
Multiple Choice
1. What is the ideal residential water pressure range?
a) 20–40 PSI b) 40–80 PSI c) 80–120 PSI d) 100–150 PSI
Correct answer: b The standard safe range for residential water pressure is 40–80 PSI, with 60 PSI considered ideal. Below 40 PSI, fixtures underperform. Above 80 PSI, the system is under stress and components wear faster.
2. A gate valve on your main water shutoff has not been operated in 15 years. What is the primary concern?
a) It will create water hammer when opened b) It may have seized from corrosion and fail to close when needed c) It will permanently reduce water pressure d) It is incompatible with modern water meters
Correct answer: b Gate valves that have not been exercised regularly can seize with mineral scale and corrosion, leaving them unable to close during an emergency. Ball valves are preferred because they operate reliably after long periods of inactivity and can be confirmed fully closed or open by the lever position.
3. Which pipe material is identified by its grey metallic color, threaded joints, and will attract a magnet?
a) Copper b) CPVC c) PEX d) Galvanized steel
Correct answer: d Galvanized steel pipe is grey metallic, has threaded joints, and is ferromagnetic (a magnet will stick to it). Copper is reddish-orange and non-magnetic. CPVC and PEX are plastic and non-magnetic.
4. What is the primary purpose of an expansion tank in a residential water system?
a) To store extra hot water for peak demand b) To absorb the increased volume created when water is heated in a closed system c) To filter sediment from the water supply d) To regulate incoming municipal pressure
Correct answer: b When water is heated, it expands. In a closed system (with a backflow preventer), that expanded volume has nowhere to go and creates dangerous pressure spikes. The expansion tank absorbs this expanded volume with a pressurized air bladder, preventing the pressure from damaging pipes, fixtures, and the water heater's T&P valve.
5. What is "standby heat loss" in a well pressure system context, and which well component does it most directly describe?
a) Heat lost through uninsulated pipes; the supply line from the well b) Energy consumed by the pressure switch when the pump is off c) Energy used by the pump motor during low-flow conditions d) None of the above; standby heat loss applies to water heaters, not well systems
Correct answer: d Standby heat loss is a term specifically applied to tank water heaters — it describes the heat that radiates through the tank walls when the heater is storing hot water. Well pressure systems are not heated systems and do not experience standby heat loss.
6. Dave Kowalski hears his well pump turning on and off every few seconds while running a faucet. What is the most likely cause?
a) A failing well pump motor b) A pressure tank with a failed bladder c) A blocked pressure relief valve d) A cracked well casing
Correct answer: b Rapid short-cycling — the pump turning on and off every few seconds — is the classic symptom of a failed pressure tank bladder. Without the air cushion provided by the bladder, there's no stored volume of water between pump cycles, so the system hits cut-out pressure almost instantly, shuts off, drops to cut-in pressure almost instantly, and repeats. Motor and well casing failures produce different symptoms.
7. What health risk is associated with copper supply pipes installed before 1986?
a) Copper leaching into the water supply b) Lead leaching from the solder used at pipe joints c) The formation of harmful biofilms inside the pipe d) Chlorine byproducts from the interaction with municipal water treatment
Correct answer: b Before 1986, standard copper pipe solder contained approximately 50% lead. As these joints age, and particularly in acidic or soft water, lead can leach from the solder into the water. The pipes themselves are not the concern — copper is safe — but pre-1986 solder is a legitimate lead exposure concern, particularly for children and pregnant women.
8. What does it mean when a pressure reducing valve (PRV) "fails closed"?
a) It allows unrestricted high pressure into the house b) It creates a restriction that reduces household water pressure below normal c) It prevents the backflow preventer from functioning d) It causes the main shutoff to seal permanently
Correct answer: b A PRV that fails in the closed direction acts as a restriction or blockage in the supply line, reducing household water pressure — often dramatically. A PRV that fails open allows full municipal pressure (which may be 80–100+ PSI) to flow unrestricted into the house, damaging fixtures and appliances.
9. Which of the following is the correct recommended slope for horizontal drain pipes?
a) 1/8 inch per foot b) 1/4 inch per foot c) 1/2 inch per foot d) 1 inch per foot
Correct answer: b The standard and code-required slope for horizontal drain pipes is 1/4 inch of drop per foot of horizontal run. Less than this allows solids to settle; more causes the water to outrun the solids it's meant to carry. (Note: This question previews Chapter 8 material and can be used as a bridge.)
10. What does the low-flow indicator (the small spinning triangle or star) on a water meter tell you when it is spinning with all household fixtures turned off?
a) Normal operation — the meter always runs slightly b) A leak exists somewhere in the house or service line c) The pressure is above recommended levels d) The meter needs to be recalibrated
Correct answer: b The low-flow indicator is designed to respond to even very small flows — below what the main meter dials can register. If it's spinning when all fixtures are off, water is moving through the meter, meaning a leak exists somewhere in the household plumbing (running toilet, dripping faucet, irrigation leak, etc.). This is one of the most useful homeowner diagnostic tools available.
Short Answer Questions
Short Answer 1: Explain in your own words why galvanized steel supply pipes that are 60 years old often cause low water pressure throughout the house, even when incoming municipal pressure is normal.
Model answer: Galvanized steel is coated in zinc to prevent corrosion, but the zinc coating on the interior of the pipe erodes over decades. Once the zinc is gone, the steel beneath is exposed to the oxygenated water flowing through it and begins to rust. That rust accumulates as scale on the inside walls of the pipe, progressively narrowing the effective interior diameter. In a severely corroded pipe, the interior may have shrunk from 3/4 inch to less than 1/4 inch. Incoming municipal pressure may be perfectly normal, but it's being forced through a pipe that's nearly blocked — so flow at fixtures is drastically reduced. This is a restriction problem, not a pressure problem.
Short Answer 2: You're buying a rural home with a private well. What are the three most important things you should do before closing on the property, and why?
Model answer: (1) Water quality testing — get a laboratory analysis for at minimum bacteria, nitrates, and pH. Well water is not regulated the way municipal water is; the buyer must verify that it is safe. (2) Pressure system inspection — assess the age and condition of the well pump and pressure tank. A submersible pump replacement can cost $1,500–$3,000+. Knowing the age and condition of the pump is critical for budgeting. (3) Wellhead and casing inspection — check for physical integrity, proper sealing, and any signs of surface water intrusion. A compromised casing can allow contaminated surface water into the well. Ideally, hire a licensed well contractor for a comprehensive inspection separate from the general home inspection.
Short Answer 3: Your home has incoming water pressure of 95 PSI. You don't currently have a pressure reducing valve. What are three specific ways this elevated pressure could damage your home over time?
Model answer: (1) Accelerated wear on fixture washers and seals — the high pressure causes toilet fill valves, faucet washers, and appliance connections (dishwasher, washing machine hoses) to wear faster and fail sooner. (2) Water hammer and pipe stress — high-pressure flow creates more forceful water hammer (the banging when valves close), which stresses pipe joints and fittings over time. (3) Water heater T&P valve cycling — if the system is closed (has a backflow preventer), the combination of high incoming pressure and thermal expansion from the water heater regularly pushes system pressure above the T&P valve's threshold, causing it to drip and wear prematurely. The valve is being operated beyond its design intent.