Update 16/11/2020 - New versions and fixes:
Fixes:
- Fixed an issue with the sponge bath interaction, which should use up water buckets properly now
- Fixed an issue with the string for the Unclog interaction
- Fixed an issue where if you cancel an interaction before it started, it would unlock buckets that were locked for a different interaction
New version:
- A new version which implements water in a different way - instead of using buckets that are created by collecting water at the well, you need to buy pails which can be filled up at the well. Interactions will use a certain amount of water from the pails
- The pail object is a clone of the milk pail from pets, and therefore requires pets (for now). Polycounts: High/Low 930/446 and can be found in misc decor
- Please see this thread for more details on how everything works including default amounts of water required for each interaction and capacity of pail 
- Also, if you run into any issues or have feedback, feel free to post on the above thread
Other:
- I have renamed the files to hopefully make things more clear. V1 is the version that uses buckets, and V2 is the version that uses pails. I also called them global and non-global rather All and Specified because I feel like it's more clear what it means. There is a global and non-global option for each version of the mod. Only pick one of the 4 files.
- If you are replacing a version of the mod that is used in a save, I would recommend resetting the town before removing the mod to make sure no sims are using any plumbing objects. You could also delete the associated objects like the well/barrels/buckets. I'm not sure exactly if anything terrible would happen especially if you have nraas ErrorTrap, but if you want to be safe then take the extra precaution
- Hmmm I think that's it

Important Update 21/05/2020


UPDATE 23/02/2020:



What is this "Functioning Well" you speak of?
It's a well! That functions!
The idea of this mod is to basically make life more difficult for your sims - Instead of being able to just use objects like showers and sinks with their invisible plumbing, your sims must first collect buckets of water from the well in order to flush the toilet, take a bath, wash dishes etc...
It's great for off-grid/ living off the land/ old timey pre plumbing era gameplay.


How does it work?
The well object itself is the decor object "The Old Dried-Up Well" from The Sims 3 Store, that comes with the Brunch at the Old Mill set.
Except it's no longer a decor object, or dried-up! Your sims can and need to actually collect water from the well in the form of buckets.
Each bucket is like one unit of water, and different interactions require a different number of units (or buckets) of water to be used. (See the Interaction List below for details)

The interactions that involve some kind of "plumbing" are replaced with new versions, that check if your sims have enough water before letting your sims do the interaction. If your sims have enough water, they can use the object as normal, and the required buckets of water will be used up.

Sims can either use buckets of water that are in their own inventory, or buckets can be stored in the stack of barrels object to be accessible across the household. So if you don't want to have to keep collecting loads of buckets for each sim, you can just collect loads of buckets of water and store them in the barrels, and all your sims will be able to use plumbing objects as normal for as long as the buckets last.
Note about the barrels: The stack of barrels is the decor object from WA, but works as an inventory to store buckets of water instead. It requires WA for now, but hopefully soon I will try and make it base game compatible. If you don't have WA you can still use the mod, but each sim will have to have buckets in their own inventory to use plumbing objects.

The well can be found in Decor Misc/Sculptures for 200 simoleons. You can place it on a community lot instead of buying it with your own funds.
The barrels can be found in Decor Misc also for 200 simoleons. These need to be placed on your home lot.
The bucket can be found in buydebug for 0 simoleons too.

It's also only active sims that need buckets of water to use stuff, so the rest of town shouldn't be walking around with terrible stink clouds around them all the time.

Technicalities


Interactions that are replaced


The numbers of buckets required for each interaction are tunable - see Tunable Values below.

There are some plumbing objects that are not affected (sims will be able to use these without needing any buckets of water). Some I may add in the future, others likely not (see below for Future Plans)
Hot Tubs, Dishwashers, All-In-One Bathrooms I feel aren't so important because they probably wouldn't fit the playstyle anyway...maybe I'm just lazy?
The Outdoor Shower and Public Shower from the Store aren't affected because they don't count as regular showers, but I may add these in to also require buckets.

Tunable Values


Translating


Installation
To install, just put the package in your mods folder. Only one version at a time
If you want all plumbing objects in the world to be off-grid for your active household then use the ALL version.
If you only want plumbing objects on lots with a well/barrel stack to be off-grid, use the SPECIFIED version.
Please note that objects already in the game before this mod is installed won't be affected. You need to sell and buy new ones if you want sims to need buckets to use them.
I'd recommend starting an off-grid save after you have installed this mod, or if you have a save started, don't build your house until after the mod is installed. That way you won't have to replace all your sinks and showers etc to get them to function properly off-grid. Not relevant anymore, the off-grid plumbing interactions should work straight away.

I would also recommend taking the mod out if you are playing a save that's not off-grid, so nothing strange happens

To Uninstall
Before you take out this mod, if you are planning on playing without the mod in save that has previously been affected by the mod (so you have been playing off-grid in), make sure your sims are not interacting with any plumbing objects when you save, otherwise the objects may become unusable. If this does happen, they should be okay if you sell and replace the objects, but I haven't tested this extensively so be warned!
It's a good idea to reset your town/reset all sims before uninstalling to make sure no sims are using objects affected by the new interactions.

Conflicts/Issues
This is a full script mod, and doesn't override any core files or resources. However, on load it does replace the interaction definitions of the interactions listed above. So if you have a mod that also does that (though I don't know any that do), either mine or the other mod likely won't work.

NRaas Shooless is an example of this. If you have both installed, the interactions affected by Shooless (Shower, Use Toilet, Spongebath) will no longer be "off-grid". The interaction names for Use Toilet and Spongebath show up blank too.

One thing to note is that because this mod changes the interaction definitions, if you have mods that adjust the ITUN files of one of the interactions that are replaced, it won't have an effect. You can edit my custom ITUN files to your liking though, they are in the package file
If you do find a conflict, let me know.
The only other thing I have found is that if you have nraas WooHooer installed, the shower WooHoo won't work even if your sims have enough water. They do the social interaction and just stop. It does work if one sim is already in the shower though, so nothing too disastrous

Resources Used



Future Plans/Ideas
I've been working on this for quite a while now, and so I really wanted to get what I've done out before it drives me insane, but even though it's pretty much done, there are a few things I feel could function in a better way. I'd also be happy to hear any ideas/preferences that you have for how this could work. Here are just some things I have thought about:


Anyway, sorry for the huge description
If you have any problems, or feedback, please let me know, and I'll try to fix it.

I hope you like it



Additional Credits:
A big thank you to Battery for all the help with my many struggles. I also used S3PE, Buzzler's STBLize tool, and Visual Studio 2017.