1. Graywater and whitewater
   Hot and cold
2. Supply and drainage
   Supply and demand

While "hot and cold" is a fair guess based on the labeling of household faucets, a building's two systems are the drainage and supply systems. One supplies clean water, and the other carries away used or dirty water.

1. Yes, sometimes.
2. No, that's unsafe.

The two sub-systems must be kept separate. Supply water might be used for drinking or cooking, so there can't be any wastewater in the supply system. It's a health issue.

1. Food-grade
   Lead-free
2. Potable
   Pareve

You might have known this one from the "Jeopardy" category "Potent Potables," which refers to alcoholic drinks, not water. For our purposes, though, it's important to know that the supply sub-system delivers potable water.

1. A faucet
   A fixture
2. An appliance
   A machine

"Fixture" is a broad term that includes sink, showers, tubs, toilets and more. An appliance is different -- it's a household machine that uses electricity, and might or might not have a water supply and drainage system (e.g., a dishwasher).

1. Gravity
   Water pressure
2. Electric pumping
   Centrifugal force

Gravity is the reason dirty water disappears easily down the drain, and through the pipes beyond that (unless there's a clog). Since gravity is everywhere, and free, it's a nifty solution!

1. An A-pipe
   A hairpin
2. A switchback
   A U-bend

This pipe is named for its shape, as a simple glance will confirm. When taking it apart, be sure to have a catch bucket or pan underneath. There's always water in the U-bend. Which leads us to this ...

1. To conserve some water in case of an outage
   To keep sewer gases from entering the house
2. To support water pressure in the pipes overall
   No reason, it just happens because of the pipe's shape

The water in the U-bend is a physical barrier against sewer gases, which are lighter-than-air and would otherwise permeate the house, causing a really unpleasant smell. A secondary benefit of the U-bend is that it's where you'll find lost rings and other objects that weren't supposed to go down the drain.

1. Augering
   Plunging
2. Using liquid drain opener
   Using a studded "drain stick"

The other three are safe manual ways to clear a clog, though a drain stick (it looks kind of like a flat plastic twig with thorns on the sides) won't reach down very far. Liquid drain opener is not recommended because it can damage the pipes, and because if the clog doesn't clear, you don't want to accidentally get the standing water, with drain opener in it, on your skin.

1. Crane
   Hawk
2. Tiger
   Snake

It doesn't take much imagination to realize that this device was nicknamed for its ability to wend its way through tight spaces and curves. This is how a drain "snake" finds a clog, which it then hooks into and pulls up up to the surface.

1. They provide air to aerate showers.
   They release sewer gases through the roof.
2. They get rid of shower or bath steam.
   Vents are not part of the system.

In the drainage system, the solid and liquid waste goes to the sewer or septic tank. But gases have to be released at the highest possible point in a building, in order not to create noxious air near ground level. Vent pipes make this possible. They also provide oxygen to aid in aerobic breakdown of waste.

1. The cesspool
   The joint
2. The spring
   The trap

We refer to this part casually as "the trap." Most plumbers have experience of taking apart a trap in order to retrieve something valuable caught there, like an engagement ring.

1. It's expensive for the home-builder
   It tends to create clogs
2. It takes up too much space
   It can allow wastewater into the supply system.

Traps are an essential part of the drainage sub-system, as we learned in another question. However, they are also a risk for clogs. Two traps are unnecessary, and so plumbers avoid the extra risk by only using one per line.

1. Keeping hair out of the drain
   Augering once a week whether there's a clog or not
2. Using limited amounts of soap and toothpaste
   Dusting the sink regularly

Hair is the biggest culprit in drain clogs. Gradually, it gets covered in that smelly black scum that lives in drain pipes, and becomes nearly solid. At that point, either the homeowner or a plumber has to take action.

1. Fish tape
   Electrical tape
2. Masking tape
   Teflon tape

Teflon tape has the valuable quality of adhering so closely to the threads at the ends of pipes that they still operate as threads. That is, they allow the pipes to be screwed together. This makes Teflon tape very useful in plumbing.

1. Sure!
   No, they don't.
2. Eh, sometimes.

Water heaters are more "plumbing-adjacent" than an intrinsic part of the plumbing system. Some plumbers might feel comfortable working on them, but others might want to call in a repair person with expertise in that area.

1. 80 degrees
   120 degrees
2. 185 degrees
   210 degrees

80 degrees is a good temperature for a swimming pool, but that's still cool to the touch. However, 210 is two degrees shy of boiling -- much too hot. 120 degrees is about as high as you'd want tap water to go.

1. The chain
   The flapper
2. The backflow device
   The trap

The flapper is the movable cap over the flush valve, which releases water from the tank into the bowl during a flush. It's an easy fix, and frankly most homeowners could do it for themselves rather than call in a plumber.

1. An outdoor spigot
   A toilet
2. A refrigerator's water line
   A showerhead

Aeration means that air is introduced into the water supply, so that less water is used but the person showering doesn't feel a lack of water pressure. However, if overdone, aeration can make you feel like you're being "sandblasted" by your shower ... so find a happy medium.

1. Water from lead pipes
   Water from a low-pressure faucet
2. Water from a rainbarrel
   Water that's used, but still OK for non-drinking purposes

"Graywater" is a term that's popular with environmentalists. For example, an eco-minded person might keep a bucket in the shower to catch some water, then use that to water plants. It's a consumer's way to get around the strict separation of the supply and wastewater systems.

1. Chin
   Elbow
2. Skull
   Wrist

An "elbow" is a small connecting piece, usually bent at a 45-degree angle. It bridges the gap between two longer pieces pf pipe and allows for a change of direction.

1. Coupling
   Pipe cutter
2. Sewage
   Waterspout

"Waterspout" is a term from meteorology. It refers a tornado that forms over a body of water instead of land. Don't confuse it with "downspout," which is a pipe that carries water down from a roof (and also isn't part of a plumbing system, but rather of a rain-gutter system).

1. Bend
   Resist rust
2. Resist freezing
   Look attractive

Braided hoses are designed to be flexible. You'll see them in tight spots, like under the sink. Similarly, a drain auger has many small plates that bend as it goes through pipes looking for a clog.

1. Baby wipes
   Paper towels
2. Q-tips
   They all are.

It's true that you might get away with throwing these things down the john, but it's really not the best idea. One of them not making it through to the main can lead to another getting caught against it, and then another ... you see where this is going.

1. A water fountain
   A laundry-room sink
2. An outdoor spigot
   A washing machine

In your garden or yard, you probably have a faucet that lets water splash directly onto the ground. The soil itself is the drainage system; no pipe is needed. Everywhere else in the home, there has to be a way for water to get into the drainage subsystem.

1. Clothes washer
   Outdoor spigot
2. Sink
   Toilet

All sink drains have built-in strainers, out of sight. But a simple strainer that fits into the drain opening, and can be removed by hand and emptied, is known as a basket strainer.

1. Controls the flow of water
   Keeps water at 130F or lower
2. Prevents leaks in pipes
   This term is interchangeable with "fixture."

Faucet knobs and showerheads are examples of fittings. They are part of fixtures, but not the same thing. They should not be used interchangeably.

1. 1 gallon
   1.6 gallons
2. 2 gallons
   3 gallons

In the early to mid-20th century, this amount was higher, closer to three gallons. Makers of plumbing fixtures have become increasingly concerned about water conservation as environmentalism has moved into the mainstream.

1. Copper
   Gold
2. Lead
   Titanium

Lead was the popular choice in Roman times, so much so that the word "plumbum," meaning lead, gave us our modern-day terms. However, as the health risks became known, copper became the go-to metal.

1. Annealing
   Corrosion
2. Erosion
   Ketosis

Rust is the most common, well-known form of corrosion. Plumbers will see a lot of this in their day-to-day work. Some metals are more corrosion-resistant that others, though.

1. Bamboo
   Mud
   Stone
2. Wood
   All of them
   All but mud

Mud would dissolve when exposed to water; the pipes would have no integrity. However, humans used all the other materials listed above, showing surprisingly ingenuity in their engineering.

1. Water pressure unexpectedly dropping
   Overheating in water heaters
2. Toilet overflow
   Water contamination

As pointed out earlier, the supply (potable water) sub-system and the drainage (wastewater) sub-systems are separate. But emergencies, like a water main break, can cause water pressure in the supply system to drop markedly and allow unclean water from elsewhere into the pipes. It's this situation that a backflow device is designed to prevent.

1. Sure!
2. Nope!

This is a specialized (and dirty) job. A company that empties septic tanks has already arranged for a place to take the waste that is approved by state and local regulations, which is a key part of the job. This falls outside a plumber's domain.

1. It'll be water-efficient.
   It'll be taller.
2. It'll be tankless.
   It'll have a warmed seat.

"ADA" stands for the American with Disabilities (Act), and doorways, stairways, furniture and fixtures that are ADA-compliant are ones built to be more easily used by people with disabilities. Such a toilet is always taller than a standard one, to allow for easy transfers from a wheelchair, or ease of sitting down for users of walkers and crutches.

1. Attractive
   Long-lasting
2. Comfortable to sit on
   Water efficient

A dual-flush toilet allows the user to flush with the maximum amount of water (usually for solid waste) or a reduced amount (for just liquid). They have become popular since the environmental boom of the early 1990s.

1. Be sure to own a good C-clamp.
   Always shut off the water at the main.
2. Use a catch-bucket when disassembling the U-bend.
   Don't eat with your hands.

OK, this one is just for fun -- but true nonetheless! Plumbers work on toilets a lot, and the job involves a lot of other dirty work -- obviously, gloves or frequent handwashing are useful.