In the various TEOTWAWKI scenarios there will probably be no organized fire companies to help out the survivors with timely a fire suppression response. Here are some simple and low cost solutions that individuals can do to suppress and fight fires that are type A fires such as paper, cardboard, wood, cloth, plastics etc. Do not fight other fire types with water . Search engine “fire extinguisher types” to learn more. [JWR Adds: You should keep at least two 10+ pound A-B-C fire extinguishers in your home, for fighting grease, chemical, and electrical fires.]
In many homes there is currently water under pressure from some supply. This can be accessed for fire suppression by various means if one takes the time to plan and practically tie into it. One of those coiled snake type 25 foot or 50 foot ½ inch or ¾ inch diameter (preferred size) garden hoses can be attached to a Y splitter ball valve from the cold water line that feeds the washing machine. You turn it on by flipping on the ball valve spigot and uncoiling the hose to move throughout the home as needed to fight the fire.
A handy person could put such a hose line anywhere in the home that water can be plumbed into such as a main hallway closet or corner area of a room on any floor. I would recommend a quality brass 90 degree ball valve as the main shut off at the end of the hard line plumbing where the flexible garden hose is connected. This prevents those nasty slow leaks from the cheaper plastic or pot metal valves.
A good quality spray valve with various spray patterns works well on the business end of the coiled hose and can very effectively give either a strong stream or various short wider spray patterns. It is not the power or volume of a real fire hose but can work well if the fire is caught in time. The key to water fire fighting is a spray or mist to quickly lower the heat and wet potential fuels. Always have working smoke detectors throughout the home and practice fire drills regularly including both coordinated fire fighting and evacuating the home. If you and the family members can get some volunteer fire training now or study fire fighting techniques from books or online this will be a big benefit later in times of crisis.
You will also want a crook staff shaped metal tube sprayer with a long metal handle. They are normally purchased to water high-hanging planters. They can be bought or made from pipe with a bending jig. It can be used for those times that fire suppression (the Molotov cocktails threat?) is needed out a window against the side of the house while maintaining some protective cover from behind a wall inside.
With a well or pressurized tank system you can add extra storage capacity by plumbing in extra pressure tanks with other valve splitters and “no leak” metal mesh covered washer hoses. The tanks can be located anywhere in the home plumbing cold water lines. Just make sure they do not freeze. This gives an added benefit of keeping your pump from cycling too much with a small tank. In an off grid or grid down scenario hook up a potable Shurflo brand or similar 12 volt pump powered off of deep cycle batteries. They are available from farm or Do-It-Yourself stores. The water can be stored in 55 gallon or similar drums and then drafted out and used to pressurize the house system by back feeding a washer spigot. These pumps usually have a 30/50 lb on off type switch built into them like a regular 120/240 volt AC water pump.
The older water type fire extinguishers which are air charged are ideal to have but they are few and far between with the modern move to and versatility of dry powder. If you have an older fire extinguisher that has a metal valve base assembly and pressure gauge you may still be in business. Those small dial pressure gauges on the side generally have a 1/8 inch NPT port which they are threaded into. You can get older spent fire extinguishers (cottage industry job potential?) from a local fire extinguisher service company.
There is usually at least one of these businesses in an area. The fire codes call for many models to be rotated out of service on time intervals or discontinued due to changes in powder formulas and such. Make friends with the owner as I have done and you can probably get all you want as they usually have to pay to haul them away because it is not worth their time to dissemble them as various scrap types.
To convert them you first make sure they are completely empty. Sometimes they leak gas or air propellant and are still partially full of powder. Squeeze the handle in a safe area outside where you do not mind killing grass or weeds. The powder kills yards dead in concentrations. Avoid breathing it as it is a slight irritant. (A twenty pound dry extinguisher also puts out a white cloud bigger than three military AN M8 HC smoke grenades and is just as irritating, for future reference). If no propellant gas is inside you can carefully unscrew the small dial pressure gauge off the metal valve base with a set of slip joint or water pump pliers. This will reveal a small port hole that goes down into the main extinguisher tank. Get some 1/8 inch NPT / Schrader Tank valves from an auto parts store such as NAPA tank valve numbers NTH 90294 or NTH 90290 (about $2 each). It is a male 1/8 inch NPT and Schrader (automobile tire) valve on the other end.
The 1/8 inch NPT end of the valve can be screwed into the port hole with some pipe dope or Teflon pipe thread (be careful not to close over the end) and you now have a way to recharge the fire extinguisher. You can take an air hose and partially recharge the tank from an air compressor and use it till it is empty or safely trigger the sprayer to make sure all the powder is out. Then take a valve cap with core tool such as NAPA part NTH 90188 ($2.39) or a valve tool NAPA part NTH 90344 (about $2.22) and remove the core which will allow the water to be forced into the tank and the air to come out. Water can be forced back into the spray hose end. To fill it simply use a garden hose and duct tape or a hose to hose with a screw pipe band clamp or any other standardized coupling designs you may devise.
The tricky part is getting the right amount of water to air mixture in the tank. Most of the old water extinguishers had a mark on the side about ¾ way up the tank side to fill them to when you removed the top. They had the luxury of being designed with a total top removable valve assembly with a big gasket seal which allowed water to be poured into by sight and the valve assembly being resealed by hand or with slip joint or water pump pliers. The valves on powder extinguishers are not practical to fill this way.
This filling process will be a trial and error on your part with your specific size and style of extinguisher. The key is to weigh the extinguisher when empty and each time you fill it and charge it with an air compressor. Most air tank compressors fill to about 100 to 125 lbs pressure. You may have to fill and charge it a few times until you get the right amount of air and water so they both run out at the same time. You usually want a little extra air pressure when the water runs out to make sure the water is all delivered under pressure. Once you have the right water/air mix write the tank empty and full weights and air charge pressure on the side of the extinguisher in marker or stamped on a brass key tag attached to the pull pin chain. This weight method of filling is similar to what is used on 20 lb propane tank fills. Check it regularly with a high pressure hand tire gauge to make sure it is still charged properly.
It is also advisable to paint over or remove the old fire ratings on the extinguisher and visibly mark the extinguisher in some manner such as a big blue stripe or bold letters H2O or WATER on the side so someone does not grab it to use it on an electrical or grease fire.
If you are real handy and have the time you can always plumb in a room by room sprinkler system that is automated (lower fire premiums) or one that just takes a ball valve to turn on when fire is discovered.
Remember that if the fire is too big or smoke too thick it is not worth your life to fight for a house. A house is just a structure. Good and prepared people make it a home. Good luck and keep the faith.