Handling Plumbing Emergencies
It's like a scene from a slapstick comedy – the kitchen faucet breaks off in your hand and water is spraying everywhere up to the ceiling and running down the walls. What do you do? Clue: Your options do not include going back in time to make better plans for this moment.
Find your shut-off valve
The most important thing you need to know about your home's plumbing is where to shut off the water. If your home is supplied by municipal water, the water meter and main shutoff valve are often within close proximity to each other, so finding the meter is a good first step.
Water meters are often in an underground hatch near the street or along an easement between properties. Look along the edge of your property for a metal lid (like a small manhole cover) marked "water meter" or just "water." You can usually remove the water meter hatch cover by unscrewing a single bolt.
Underneath, you'll find a rotating valve similar to an outdoor spigot, or a valve with a metal flange. The latter may require a pipe wrench to operate. In either case, turn the valve clockwise until it stops to shut down the water supply.
Warning: Although you may need to do this quickly in an actual emergency, if you're just testing you may need to first turn off the water intake valves to appliances like water heaters to ensure that your test does not cause any damage. Check your owner manuals on these devices and take appropriate steps before shutting off your home's main water supply.
You may, of course, also have a water shut-off valve in your basement or crawlspace. Usually this would be along the pathway of the main water line and just inside the house.
Other shut-off valves
Each plumbing fixture, such as dishwashers, faucets, water heaters and toilets, will often have its own dedicated shutoff valve. For freestanding fixtures, such as toilets or pedestal sinks, the shutoff valve can be easily located on the water supply line between the floor or wall and the fixture. Kitchen sinks, dishwashers and cabinet-mounted sinks would normally have their shutoff valves under the kitchen sink.
Shutting off water to fixtures mounted flush against the wall -- bathtubs, showers, etc -- may be harder to do locally because the valves (if they exist) may be hidden behind drywall.
Of course, finding the valve is one thing; whether you can turn it off with your bare hand is another. Because they are so rarely used, these valves may be hard to turn without a wrench. Try loosening each of these valves with some household spray oil so you'll be able to shut them off quickly if you ever need to.
You've just completed a satisfying natural bodily function and flushed the toilet. You're still pulling up your pants when you realize the toilet is clogged and the water is rising closer and closer to the rim. Quick - what do you do?
It's always recommended to immediately turn off the water using the valve behind the base of the toilet. Unfortunately, in most homes these valves are rarely used so you may find it is too stiff to turn by hand.
Don't panic and remember that the water supply line's job is to fill the tank, so what truly matters most is preventing any more water from going into the bowl. Take the lid off of the tank (but don't drop it on the tile floor because it will break) and make sure the rubber flapper has fallen back into place. If it's still open, reach in and push it back in place to stop the water flow. (This is no time to be squeamish; tank water is not yet sewer water).
If you are unable to prevent water from flowing from the tank to the bowl you absolutely need to make the water stop coming in, and if you already have the tank lid off the fastest way to do that is to lift up the float ball until the refill valve shuts off. If your toilet does not have the classic float ball, look for other moving parts (usually on the left) that slide upwards with the water level. Lift up any part that moves freely until the water intake valve shuts off. Keep it held up with one hand while you struggle to close the stubborn shutoff valve. (Note to self: Spray some oil on this for next time).
Once you have prevented further water flow into the bowl you have some time to figure out the next move. If the bowl did overflow onto the floor, clean it up before you proceed or else you will track bacteria from sewage water elsewhere in the house. Now you are no longer in a plumbing emergency situation and can focus on how to unclog a toilet.