I have two boys and I liked the idea of installing a urinal in their bathroom to save water. I especially liked the idea of a flush-less urinal such as the H2Zero or the Kohler Steward. I am not talking about a bucket of sawdust, I am talking about a space-age ceramic urinal that is so slippery you don’t need to flush and includes some sort of clever one way valve or fluid trap so there is no smell. I talked more about the conspiracy against these flushless urinals in this post. These modern wonders are now standard in public institutions, airports, etc. The US Army Corp of Engineers has specified their exclusive use in all new military installations based on their ability to save water/money…
So, I did some cost analysis of my own.
I went to the Grainger website and found a 1 hp submersible well pump that would be similar to what I would need for the new house (no city water or sewer). This particular one says it uses 230 Volts and 9.8 Amps… Multiply those together and you get 2.254 kWs of power required. It says it can pump 20 gallons per minute at 100 ft depth, multiplied by 60 minutes/hr gives 1200 Gal/hr with 2.254 kWH of energy. Divide the energy by gallons and you get 0.001878 kw/gallon, or lets multiply it by 1000 to get 1.878 kW/kGal.
Next, I needed to find my cost of power. If I look at a power bill it adds a whole bunch of charges including nearly 9 cents per kWH for the energy and 5 cents per kWH for the “delivery charge”. There were a bunch of other taxes and “charges” but since they are fixed costs and not variable with energy use, I am leaving those out and going with $.14 /kWH.
So then you just need to divide the $/kW by the kW/kGal to get 0.26 $/kGal. That is just over a shiny quarter dollar per thousand gallons… I can already guess that it is going to take a lot of flushes to justify the urinal ;).
Then I look into how much my current toilet uses… My toilet was installed in 1992 when they thought that 3.4 gallons per flush was a good amount (sometimes, I need to flush twice, so maybe that was conservative if you know what I mean). I have installed a low flush valve with a one-two option, but lets say my baseline is the 3.4 gpf standard. If I imagine that each of my boys would use the urinal four times a day, and I toss in a couple of trips for myself, I get to a nice round 10 flushes a day or the less round 3650 flushes per year. Since the alternative is the regular toilet, I could say that the flushless urinal would save me 3.4 gpf * 3650 flushes/year = 12410 gallons per year. At 0.26 $/kGal multiplied by 12.410 kGal/year, we get 3.23$/year.
If I figure that even a cheap urinal costs almost 300$, and then you still need to pay to have it installed, we would be talking a pay back of over 100 years. It is easy to imagine that an army base or football stadium with hundreds or thousands of flushes per day could easily reduce the payback time to just a few years or months, but this is using well water and my own septic field…
So what if I got water from the city? Well, I currently pay a water and sewer bill and see that it shows a charge of $3.64 per 1000 gallons for the water and then $4.83 per 1000 gallons “sewer rate”. This adds to more than 32 times more than the cost of well water, and would significantly reduce my payback time to just 3 or 4 years. So even if the urinal math doesn’t work out for me, maybe it will for you?
While we are on the subject of residential urinals, I am reminded of a clip I saw on TV years ago where Penn Jillett (of Penn and Teller) was giving a tour of his home and office. I couldn’t find the clip on line, but I recall at one moment he pointed to the urinal in his home/office bathroom and said “I know what you are thinking, who needs a urinal AND a sink”.
So, out on my rural property, with my low cost well water, it is hard to justify a urinal financially. But what about for environmental reasons?What about saving water? Well (no pun intended), I live in the great lakes basin along with a huge portion of the worlds fresh water. It is even shown on the back of that quarter we pay for the 1000 gallons. I have a 1 acre pond on my property and there are many small ponds, lakes and marches near by, so I can’t really say that water conservation is much of a concern. After the water gets used, it is sent down to my own septic field where it returns to the local environment as it has many times before. If I lived in the dry south eastern USA, I could probably justify it based on water conservation, but not in Michigan.
I came up with a weak argument that it would still work if the power to well pump were out, but it would only help the men in my family and we could just go in the woods if times got tough. ;^)
So, will I still get the urinal? I am still working on it, stay tuned.