They’re also toilet they make that have 2 different flushes for your purpose. i.e. pull up for #1 and down for #2. it uses less water for #1 and more for #2. That would alleviate some of your pressure problems noted in the comments above.

Regarding the savings quoted, the range of water use varies greatly across the country. The average is 90 to 160 gallons, with a portion of that being for outside irrigation. Inside water use is closer to 60 to 80 gallons per day and the statistical percentage of use by the water closet (toilet) is 26.7. Because the basis for savings in the article are averages and rounded off numbers the results are flawed.

To get down to the nitty gritty, when you replace a 3.5 gpf with a 1.28 gpf, the savings per flush is 2.22 gpf. The statistical average of flushes per day per person is 5 to 6. If for this example we use 6 flushes per day, times 2 people the water savings is 26.64 gpd. For a 30 day month, the savings would be 799.2 gallons.

Just as with water use, water rates vary around the country. Some areas have a flat rate (i.e. Sacramento) where no amount of water savings will put any dollars back in your pocket. I’ll cover the other extreme in a few lines. Another savings to consider is sewer discharge rates which can be 2 to 4 times as much as the water rate. BUT sewer rates also vary, in some areas sewer costs are also flat rated.

If you’re in an area with flat rates, nothing you do will have any monetary benefit for you. But you may avoid water shortages or an increase in the flat rates you are now charged.

To compute your actual saving you have to find out what your water and sewer rates are. Typically they will be on your bill and stated in CCF (one hundred cubic feet). Since a cubic foot of water is 7.48052 gallons, one CCF is 748.053 gallons. If that is the case add the water and sewer rate to get the combined rate. Divide the gallons saved by 748.052, and multiply that by the combined water/sewer rate to find out your dollar savings.

The highest water rates I’ve found are, believe it or not, in Seattle at 3.406/CCF. The sewer rate is also quite high at 6.56/CCF. The combined rate is 9.97/CCF. If my water savings as shown in my example is 799.2 gallons per month, the dollar savings calculate out to $10.65.

If however I’m in Chicago where the combined rate is 1.772 the dollar savings is $1.89

A few more sample of the dollar savings per month based on combined rates of a selection of cities:

Albuquerque $4.06
Atlanta $8.67
Colorado Springs $5.05
El Paso $3.51
Fresno $2.91
Los Angeles $5.09
Omaha $2.47
Portland $8.14
San Francisco $7.58

The median for the 50 largest US cities is $4.59.

With a 10 year life span the saving for the median would be $551.35 on a $300 investment. Just take into account that is if the water and sewer rates stay the same.

I hope this info is helpful.

We’ve never had a problem with the flushing power and it barely uses any water at all when it flushes. I think these have gotten much better over time.