Some people haul in their water and distribute it to individual systems as it is needed via a bucket or a jug. While this can work in the short term, over a long period of time it can become a pain [literally]
Several people I know do this because they are afraid to plumb. Dee Williams said so herself in several of her videos that this is why she doesn't have a shower. Want to know the worst part? An off grid plumbing system is WONDERFULLY easy to build and maintain. Why? There is no need for pressure in the pipes. No pressure means VERY little chance of leakage and even if you do spring a leak, it will be very easy to mend.
Then comes to mind the fact that some people want to live on the grid [you weirdos :P ], or at least to have the option, so that if the time comes where they are uncomfortable living off grid, they can "plug in" and have the reliability-ish of shore power.
* I say reliability-ish because within the last year I have been without water twice in an on grid home...so it's not always 100%
So what do you do? You want plumbing, but you don't want problems. You want grid water, but you don't want to have to contract someone to make sure your pipes won't leak on you. Oh, and you want to be able to go off grid as well. huh...
OK, so the system we built is primarily designed to be off grid and to run off gravity power (because it is free and abundant). Basically all it is, is a water tank in the loft storage area(above the highest faucet that will need water). the tank has a pipe running to everywhere that needs water [shower, sink, and toilet if you have a water toilet] and while this sounds like a huge feat it's only a few parts and maybe a few hours worth of work:
1. Go to a big box home improvement store and pick up a rain barrel spigot kit like
This cheap one
or This better one
But you can build them cheap from a male and female pipe union, a drilled hole, and a ring of silicone to make the seal. (They work better with a rubber washer type material for the silicone to stick to as it adheres to the drum.) [Maybe $7 in cost for metal parts, $15 for brass.
You DO want an overflow port at the top of your barrel in case the check valve fails while you are hooked up to the grid. (if you don't you can flood your house.)
2. Get a FOOD GRADE barrel of the desired size for your house it HAS to be food grade or you may have some nasty stuff leeching into your water which is no bueno! You want this barrel to have a removable top lid. I am going to use a 30 gallon barrel for my system, but most people will need at least 55 gallons. You can get food grade barrels cheap on websites like Craigslist.org.
3. Get a toilet style stop valve like:
or this one
There isn't really a "better" between the two types.
4. Get all the pvc fittings you are going to need. I am not giving you a parts list here because this is completely custom. the smaller the pipe, the lower the cost, but the less water that can flow through the pipes without pressure. 3/4" pipe would be my choice for two reasons. First, I have experience with the size and think it will fit me just fine. Second, 3/4" is the standard size for a garden hose to plug into so you save money on expensive larger hose or adapters to get down to 3/4 inch.
WHAT TO DO:
Since this build is completely custom I can't really give you step by step instructions, BUT I can tell you enough to give you an idea of what you are supposed to be doing [EVEN IF YOU HAVE NEVER EVER EVEN HEARD OF PVC BEFORE! (aren't I nice?)]
Remove the lid to your barrel (The barrel MUST have a lid so you can get inside to install all the parts!)
Make a mark around 3-4" from the bottom of the barrel (Far enough to where you have a good flat surface). Figure out what size hole needs to be made according to your spigot kit. Drill a hole where you made your mark. This is going to be your "water out (house)" hole
Now make a mark near the top of your barrel. [3-4" from the lid] Again, figure out what size hole needs to be made according to your spigot kit. Drill a hole where you made your mark. This is going to be your "water out (overflow)" just in case your toilet valve fails or leaks and fills your tank all the way to the top. This will prevent water from pouring out into your tiny house. You can push two nails through the "Water out (overflow)" hose about a foot apart and silicone the leak closed. You have the option of installing an alarm here to let you instantly know when you are overflowing. When the water touches both nails it completes the circuit and the alarm would sound (and if you are handy with arduino you can program it to send you a text or an email when it happens)
Install your spigot kit as per the manufacturers instructions. most kits will be two rubber rings, the spigot, and a nut. Take one rubber ring and put it on the spiggot, thread the feed end into the hole your drilled, put the other ring on, then tighten down the nut until you create a watertight seal. For extra measure, you can take silicone caulk and caulk the parameter of the rubber rings.
Now comes the hard part. Drill a hole in your lid in the center, this hole should be the same size as the pipe you are working with. It doesnt really matter where it is, as long as it isn't near the edge. Take two "unions" and a short piece of pipe, this pipe should be about 1.5" in length. Take pvc primer and prime the insides of the two unions as well as the short piece of pipe. [Do this in a well ventilated area]
After that has dried, take pvc cement and cement the pipe in one of the unions. You should have a small bit of pipe sticking out of the union. Now insert the bit of pipe into the hole you drilled in your lid. Cement the remainder of the pipe and press on the other union. You should have a tight seal around the hole. For extra safety, you should take silicone caulk, and caulk around the edges of the union and the lid. Let this dry for 24 hours.
On the outside of the lid, cut another length of pvc the same size as you cut for your unions and cement it in place. Next cement a [whatever size pipe you are using] to 3/4" male threaded adapter. (you could probably replace the top union with the 3/4" male threaded adapter and save 50 cents in parts.)
Take a male to male hose adapter and attach it to your 3/4" male threaded adapter [the reason I said to do it this way is that the threads are a bit more coarse on a hose thread than a pvc so using a straight 3/4" female adapter may lead to leaks. Using the hose adapter gives you an O ring to press on and help seal out leaks. This also allows for you to easily disconnect the hose from the tank if you need to without sacrificing the seal.
While your lid is drying you can build the fill level check valve.
You want your check valve to be vertical so we need to create a J shape out of pvc pipe to redirect the water coming in from the lid back upwards for the valve to function correctly.
To build the first leg of the J you need a length of pvc pipe 6-10" longer than your toilet valve is tall. Now take a 90 degree elbow and add a length of pvc pipe that is 2-4" longer than your toilet valve is wide [to provide clearance for the float piece to function correctly] now add a second 90 degree elbow to the end of the bottom of the J facing back upwards.
Your toilet valve is probably going to have a different sized fitting than your pvc, so get the correct adapter(s) and fit them to your pvc pipe. [Ask an employee for help if you need to, it doesnt have to be pvc, my first adapters were brass because we had them on hand.] Now install your toilet valve onto the lower part of your "J".
Now cement the J piece into the inside of the lid's side of the union. Make sure the float can function.
Set the lid aside and let dry.
While that is drying you can set up the barrel and run water for the rest of the house. It really is no big deal, just take pvc pipe and run it from your tank to wherever you want your faucet to be. For efficient flow of water, use curved 90 degree elbows for turns, if those are not available, use two 45 degree elbows. To create a faucet you can install a ball valve to the end of your pvc pipe. Alternatively you can use an adapter and install an actual faucet for a more professional finish. The same applies for a shower head. I will make a post later on how to build a "rain" showerhead which is my favorite.
After all the pvc cement is dry you can install the barrel and run a hose from your barrel outside. You can either drill a hole in the side of the house for the hose, or just run it out the front door. Normal garden hose can not handle grid pressure for long periods of time, it will leak. If you want to have this system hooked up to the grid you can get some reinforced hose that can withstand 200 psi or better and have it constantly hooked up.
HOW THE SYSTEM WORKS:
The system uses the same exact same principle as a toilets water tank. The grid is hooked up to the toilet valve which will allow water in once the water drops below a certain set level. Once the water raises back to that level the valve cuts the water off and the tank remains full until water is drawn from it.
Something I learned a long time ago that really helped me understand water workings was the quote "Water always tries to find its level."
What this means is that if you have water running through a system, it will always try to get back to the height of the water's level. An outlet anywhere under that level will always lead to running water, and an outlet anywhere ABOVE that level will never yield running water. This also means that the lower the outlet, the faster the water will travel because there is more pressure above it from the other water pushing down.
I hope this helped! Have fun with it!
Below is a general pic of what the system will look like. (I will post more pics when we get the long house off the water grid.)