Distribute the fresh, potable drinking water through the building at code required pressure. Water from the city, cistern, your well, etc. can all be hooked up to the WOM. Automated systems can manage the connection to multiple water sources to keep the cistern supplied with water.

The cisterns elevations are designed to gravity feed the water pumps and filters. The elevation of the water pump is low to the floor level of the building. The water pump pushes water into a pressure tank.

Catchwater Organizing Module - WOM

the WOM

The WOM, Water Organizing Module filters and pressurizes fresh, potable drinking water for human consumption and use. The WOM can be added to any existing building to improve water quality.

DC Pump. Good and simple. Can be repaired with new parts.

The W.O.M. (Water Organizing Module) starts with a high flow strainer with a 50 mesh screen. You can see through the filter cartridge so you can see whether the filter is dirty or not. It just gets the debris the silt catch doesn’t get out of the water to protect the pump.

Then the pump pushes the water though another filter, a 500 mesh filter. Then, the water goes to a pressure tank. The pump is builds up code required pressure in the pressure tank. The pressure tank is sized for the water uses of the building.

After the pressure tank, the water goes out to the building for all normal use of water except for actually drinking the water.

On the WOM, after the pressure tank line, there is a line though a 1000 mesh filter then to a high flow drinking water filter. The 1000 mesh filter protects the drinking water filter. The fresh, potable drinking water is distributed throughout the house where fresh, potable, drinking water is used. Usually at every sink, there is a separate faucet for the fresh, potable, drinking water.

Aside from the autonomy and security that comes with rainwater harvesting and filtration, there are many other advantages that are worth highlighting.

  • Healthy drinkable water without ANY chemicals
  • Water harvested from local systems is used to produce and sustain life before being returned to that exact same system. (i.e. No mass water displacement offsetting natural ecosystems, which is what’s happening with the water grid)
  • Billions of dollars are spent annually every year on maintaining and expanding the water grid, which is incrementally polluting our water supply lines from coast to coast. If the solutions proposed here are applied on a large scale, it would eliminate those costs and mitigate the poisoning of our earth. (and our bodies when we drink tainted water)
  • If there is an incident with water contamination, the problems are isolated and not dispersed over an entire region.
  • If applied on a large scale, it would also return tons of water back into the ecosystems. The need to have tens-of-thousands of miles worth of large pipes filled with pressurized water would no longer be necessary – that’s a significant net gain in available water.

Installing the WOM

You will need wall space that is at least 4 feet tall and 2 feet wide to install your WOM. This space will need to be plumbed with lines that correspond to the inlet and outlets on the WOM to insure a neat and tidy installation.

It is recommended that between the WOM and the wall it will be mounted to there be a 2 inch piece of rigid insulation. This will keep the noise from the pump from resonating throughout the wall. Once this piece of insulation is in place, you can screw through the WOM and the insulation behind it right into the wall. The unit should be screwed in six locations. One screw in each of the four corners, one screw centered on the top and one screw centered on the bottom. Now your WOM is mounted.

Mounting The WOM

You have a lot of flexibility in choosing how to connect each core component. Some people chose a long horizontal setup to create a left-to-right flow for simplicity’s sake. There are plenty of other designs, what’s important is that it works!

To attach the plumbing to the plywood, we used a bunch of hooks that could be tightened using bolts. Hardly any nails or screws were used. The reason for this is because if a problem emerged, we could easily detach it from the board for maintenance.

Plumbing in the WOM

In the picture above, the WOM connections are labeled. The line labeled “In from cisterns” should be connected to the cisterns. In order for the pump to be primed easily the water source should be at a level either higher or equal to that of the WOM. This valve is 3/4” female iron pipe size (IPS) and should adapt to the cistern line with no modification.

The next step is to connect the two yellow valves labeled “To house” and “To pressure tank”. These are 3/4” female IPS as well and should easily connect to the household plumbing. The valve labeled “To house” is the pressurized supply to the household fixtures as well as the hot water heater and should be connected to those.

For the valve labeled “To pressure tank”. Earthship Biotecture strongly recommends the use of a pressure tank in order to eliminate short cycling the pump and maximize the water boards performance during times of peak demand. This valve gets connects to a designated line for the pressure tank.

At all of your sinks you should have a designated drinking water faucet with its own designated plumbing line. This line connects to the 1/2” brass outlet labeled “To drinking water spigots. This designated drinking water is taken through an extra filtration step to rid the water of any harmful organic or inorganic material. It is the only water suitable for drinking.

Once all of the plumbing has been connected it is time to connect the electrical.

WOM Electrical

Before starting to connect the electrical you must first check to make sure the voltage rating for the pump matches the supply you intend to connect to it. It will either be 12 VDC, 24VDC or 110 VAC. They cannot be connect to other than there recommended power or else immediate pump failure will result and any expressed or implied warranty will be voided. Once you have verified the voltages are compatible it is time to wire the power supply to the WOM.


Just above the pump on the WOM there is a junction box with a switch. The switch obviously turns the pump on and off and constitutes the disconnect required by most electrical codes. Open up the box by removing the switch and adapter plate. There is no reason to disconnect the switch, there should be adequate wire in the box that it can dangle out of the way, simply slide the adapter plate over it.

Going into the box there is a short piece of wire labeled “guide wire” above. Where this wire is connected in the box is where your power supply should go. Just remove the guide wire and connect your power supply to the corresponding wires. The wire you are connecting should also replace the guide wire through the strain relief connector attached to the box. Essentially when you are done the new wire should be connected and in the place of the guide wire.

After you are confident everything is in order replace the adapter plate and reinstall the switch. It is strongly advised that a qualified electrician do the installation if you are in anyway unsure of how it should be done. Now that this is done it is time to fire up the WOM.

Initial start up

Before starting the WOM for the first time double check and make sure everything is connected appropriately. Also the pressure tank should have a pre-charge of 28 PSI, which 2 PSI less than the cut in pressure preset by the pressure switch. Once all of this is done and you also have water in the cistern(s) it is time to try it out.

The first thing you want to do is open the valve coming from the cisterns. Then open the valve to the the house. Next open one of the cold water faucets in the house and turn the power switch on the WOM to the on position. At this point the pump should be running with a quiet hum, this means it is not primed. As the water moves from the cisterns toward the pump it will start sounding distinctly deeper. Now water should have started coming out of the faucet you left open. Once it is coming out in a steady steam shut the water off, immediately the pump should shut off. Now open the valve to the pressure tank and the pump should turn right back on. The larger the pressure tank that you have the longer the pump will run. The pump should automatically stop at 50PSI. Next open the faucets in the house and run them until no more air comes out. I recommend you test the WOM through at least one complete on/off cycle. It time to check for any leaks, if any are found repair them appropriately.

Parts and Pieces: Assembly

The water organizing module manifold is assembled using schedule 40 PVC pipe, glue, thread tape, valves, clamps, bibs, tubes, adapters and fittings. PVC valves tend to leak, so we integrated brass valves throughout as much as possible. The Rusco spin down filters came with PVC flush valves, so we kept those as is.

At the hardware store every part was laid out on the floor so we could be everything mapped correctly.

Designing the system was extremely difficult because I had no experience with plumbing or anything really relevant. My cousin Dan and I built a PVC version of “Redneck Golf” once, that’s about it. It took several weeks of researching all this stuff before I could really wrap my head around it. Some of the most challenging parts were learning what things were called, what they were for, where to find these items, how to assemble them together, etc. In the hardware store, I physically laid out all the parts on the floor just to be sure it was mapped correctly. Some employees and strangers there were happy to offer helpful advise too!


Here are some basic tips:

  • PVC threading is different than hose threading. There are different types of tubing as well that require adapters or clamps to connect to PVC.
  • CPVC is best for hot water applications or dealing with chlorinated water.
  • MPT and FPT are standard pipe threading. The “M” stands for male, the “F” for female. NPT (National Pipe Thread) is exactly the same, just a different name. MIP and FIP are the same as MPT and FPT, the “I” just stands for “iron”.
  • Schedule 40 PVC is great for handling the Water Organizing Module pressure. If you ended up getting a different size like schedule 80, know that it only effects the inner diameter size.
  • If you’re outside of the US, you’re dealing with entirely different acronyms – good luck.