Dual Flush Toilets

Dual Flush Toilets

Things to look for when buying a new toilet (not necessarily in order of importance):

1. Low water consumption (if you flush your toilet 20 times per day, a savings of 20-100 gallons/ day is possible if you replace your toilet, depending on how old it is. As much as 35,000 gallons per year.

2. Durability, low maintenance

3. Flush performance & flushing mechanism: Recently there has been great advancement in the design of the trap and flushing mechanisms to achieve superior flush performance with far less water. Powerful flushes can be noisy..but they do help keep the bowl clean.  Pressure-assist toilets require at least 25 psi of water pressure to function correctly. If in doubt, you can check your home's water pressure with an inexpensive gauge (available in hardware stores). If your home has low water pressure, go for a gravity toilet, which can work well with levels as low as 10 psi.  Some of these mechanisms can be more expensive to repair or replace. 

4. Surface area of water: I have noticed that more surface area means waste does not land directly on the porcelain

5. Ease of Cleaning: Does the bowl stay relatively clean with use? (S.A. of water and power of the flush can help keep the bowl clean) Are their a lot of nooks and crannies that gather dust and dirt?

6. Comfort: How does the flushing handle feel? (you will probably grasp this handle thousands of times each year..so consider it a major quality of life issue. Flimsy handles are depressing. Is the seat comfortable? Is it the right height? (ADA models that are higher are available) Is an electric seat warmer a vain and frivolous luxury or a necessity? Oval seat or round seat? Oval seats are considered more comfortable if you have the space.  Acoustical comfort: Soft close seat to avoid the loud echoing noise of a carelessly dropped lid.

7. Aesthetics and style: color choices, compatibility with bathroom style, seat material

8. Ease of installation

9. Dimensions There is some variability in toilet size...and shape, be sure you select a toilet that fits with adequate clearances on all sides. One key dimension that varies is the distance of the waste-line from the back wall.

10. Availability of replacement parts

11. Price including available rebates

12. Embodied energy of the toilet: how much energy does it take to ship a toilet from Australia or Japan? How much energy goes into the fabrication of the toilet? Is it made from recycled materials?

13. Recyclability: will the manufacturer take the toilet back and recycle the parts when it is made obsolete by future advancements in the technology?

I recently invested in two new toilets for my residence in Berkeley, California. Like most people, I had never bought a new toilet before. So I did some research. I searched on the internet for sites comparing different models and offering performance test results. I visited local suppliers, such as Home Depot and inquired about the models on the floor. For example it is possible to purchase a shiny new toilet for less than $200, seat and wax ring included. When I inquired as to why this model was so cheap, I was told that the trap was not glazed...and therefore is easily clogged with waste that cannot smoothly slide through to the plumbing line. On a side note, I discovered that Urban Ore, a building materials salvage yard in Berkeley, California sells used toilets and toilet seats. The used toilet seats are way overpriced. In fact, they typically cost more than brand new ones. Used toilets are a better deal...but In my opinion it makes no sense to spend the time and energy refurbishing and installing obsolete technology, no matter how charming. Perhaps some creative person will discover a great use for obsolete toilets and they will have a second life.

Back to the topic. EBMUD has good information on the performance of different models and also available rebates for purchasing what they call a "High Efficiency Toilet" Performance ratings depend on water usage and also the success of the flush. A toilet that uses little water but needs to be flushed several times to eliminate the waste is clearly worthless. The EPA has a good resource for all types of watersense fixtures.

I was motivated in my selection by a concern for water conservation, and I admit that there is some question in my mind about the trade off of the disposal of my perfectly good but waterhog old toilet and the water savings. I have not done the extensive research that would be required to determine the precise effect of my toilet replacement on our happy survival as a species, but since I am an architect I figured it was worth a bit of consumption to educate myself.

Below you will find a comparison of the two toilets that I chose. In summary, they are both fine, except for the problem of not enough water in the bowl to keep waste from smearing the porcelain. The solution to that problem might very well be a device called flushmate. This is a pressure assisted flushing system. According to the manufacturer it forces waste at 70 gallons/ minute, strong enough to clean the bowl with every flush. The pre-flush water level in the bowl is also higher, which helps keep the bowl clean as well. Many different toilet manufacturers offer the flushmate system at 1.6 gal/ flush, 1.0 gal/flush, or less. The flushmate website has links to them. Make sure you claim your rebate money if you install one of these high efficiency toilets!

The two toilets that I selected were the Caroma Caravelle and the Toto Aquia

Both have a dual flush mechanism, allowing the user two options for water usage depending on what they are flushing and how much water might be required. (1.6 and .8 gallons for the caroma and 1.6 and .9 gallons for the Toto. Compare this to older models that typically use between 3 and 7 gallons per flush) Both have what I would descibe as modern lines...mainly an aesthetic based on functionality, not traditional toilet aesthetics and nostalgia. Both have sleek bases that are easy to keep clean...not a lot of nooks and crannies for dust and bathroom scum to collect.

Other assessments:

1. It seems like even less water is needed for flushing only urine. (the caroma does better in this area)

2. I recently tiled my bathroom floor ( a couple of years after the caroma was installed.) Unfortunately I did not carfully study the unusual way that the caroma is meant to be installed with screws into the subfloor at the rear. I drilled holes through the tile and subfloor and now there is nothing for the screws to bite into. So my toilet is not solidly attached to anything and therefor rattles around a bit.  Real bummer.  I prefer tha standard american attachment method.  

3. Both of these toilets have one BIG problem.

Because of the low water level in the bowl, and a low surface area of water, they need to be cleaned with a brush every time someone defecates. I am all for saving water, but I am not sure how this problem can be solved. Perhaps there needs to be a pre-dump lever to add more water to the bowl when user anticipates taking a dump. Maybe you can learn to aim.

Time to look into waterless composting toilets?

I have first hand experience with the Toto Aquia and the Caroma. Definitely mixed reviews...I like the way they look and they are sleek on the outside...easy to keep clean...but the bowl staining is a problem. My brother chose a Gerber toilet (highly recommended by Terry Love) that has a power assist flush and a large surface area of water. I don't think it is very good looking, but if aesthetics are not a primary concern for you, this might be a good choice.

This toilet also comes in a wide array of colors...which might appeal to the more daring among you.