Dual Flush ToiletsWe recently wrote a post about dual flush toilets for a customer of ours. We were so surprised about the water savings and payback you get when you upgrade from your old toilet to a dual flush toilet, we decided to add this post.  I was always of the opinion that upgrading to a dual flush toilet did save money in terms of water usage, but not enough to make it worthwhile from a financial point of view. There are some situations where it makes sense from a purely financial perspective to upgrade your toilet. Of course there are esthetics to consider and also that you now have a modern toilet instead of one that dates back into the 80’s or even older.

If you can remove your old single flush toilet and install the new dual flush toilet yourself, then you probably can break even or even get a payback on your investment in less than 10 years. We did several calculations which will support this assertion, however you will need to adjust it to your own situation in terms of water cost as well as whether you hire a plumber or not. Hiring a plumber significantly increases the cost of the new toilet.

Dual Flush Toilet Costs

Here are the assumptions we made and we would be interested in your views, adjustments we should make to the assumptions etc. Here we go:

  • New Dual Flush Toilet $200.00
  • Installation $100.00
  • Parts $30.00
  • Rebate $oo.oo

Total Cost $330.00

Some states or municipalities may have rebates as an incentive to save water. We do not have an incentive, however if yours does include that rebate above when you calculate your overall cost of installing a new toilet. Also if you can install the toilet yourself, you can zero out the installation cost of $100.

Cost Assumptions for Upgrading

  • Old tank size:  5 (gallons)
  • Water Rate /CC Meter:  $0.565
  • Gallons / CC Meter:  264
  • $/gallon: $0.0021
  • Sewer Rate:  1.66 (Our water rate is increased by this factor)
  • Cost per flush: $0.03
  • Flush per day: 10 (average rate, adjust as you see fit)
  • Cost per day:  $0.28
  • Days per year:  365 (If you are on vacation, you may decrease this number)
  • Cost per year:  $103.89
  • Number of years:  6.5 (Number of years to achieve payback for our scenario)
  • Total Cost:  $675.31
  • Savings Rate/Flush: 0.5 (We used an average savings of 1/2)
  • Net Water Savings: $337.65

Return on Investment $7.65 (This is the savings when it turns positive for us at 6.5 years. You can adjust the number of years until you get a positive result, which is the number of years that it will take to pay for the toilet.

There are some other assumptions that we did not bother to include which could have a significant impact on the results.

Rebates for example could have a dramatic impact and cause the payback to be decreased significantly. Also the cost of water is going to increase a lot over the next 10 years. No one knows how much and it will be different in each state. This will only increase the savings even more as rates rise. Completing the installation will also save you a great deal of money and reduce the payback period even further. finally these calculations assumed one toilet in your house. Most homes have several toilets so you will have to add costs for the number of toilets you have and split the number of flushes between toilets.

Can You Get any Rebates for Dual Flush Toilets

We played around with the numbers a bit and found that if we installed the toilets ourselves, purchased them on sale and received a rebate, we could get the payback period down to 5 years which is pretty good. It does demonstrate just how practical and economical it can be to install dual flush toilets and how much you will save in water compared to your old toilets.

We have not taken into account any advantage we might have gained in terms of resale value of our home. It will definitely have an impact on the sale price, however how much is anyone’s guess.

If you have crunched the numbers for the location were you live and are able to get the numbers even lower, let us know. We are trying to save money and update our homes at the same time.