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Environmental Designworks Sink Positive Tank Lid Sink


Plain and simple, I think the Sink Positive may be one of the best green inventions I've ever used.  After you flush any toilet its water tank refills for the next flush.  All the Sink Positive does is route that refill water first through a spigot (so you can wash your hands with it -- it's clean, just like it comes from the sink!) and then it sends the now "gray water" back into the toilet tank.  I just can't believe how intuitive, simple, and water-saving it is.


Actually, most impressive/scary is how much water actually goes into each toilet flush (even a low-flow!).  Whenever I've used this, I always have at least twice as much possible wash time as I need.  Totally amazing and every toilet should have one.  :)  I'd give it 10 stars if I could!


Pros: Works, saves water, makes a good conversation piece

Cons: None

Think about it: every time you flush your toilet the tank and bowl refill with clean tap water. Cleaner than a lot of people in the world have to drink! Here's a great way you can save a gallon or two each time you flush.

People sometimes get confused about how this thing works, and think they're washing their hands in toilet water. That is not accurate. What you are getting is water straight from the pipe in the wall. The water goes into your toilet AFTER you wash with it and it drains out the small basin hole.

With me? So here's what happens:

1) You do your business in the toilet

2) Stand up and flush

3) CLEAN water starts pouring out of the little faucet

4) You wash your hands with it

5) As you do so, the toilet bowl fills up with soapy water from your hand wash


The water savings comes from NOT walking over to the sink to wash your hands with MORE clean water right after you flush. The soapy water only drains into the toilet bowl, not the tank, which keeps things a lot cleaner. All you will notice, really, is a little white cloudiness in the toilet bowl water from your soap.

The water runs out of the faucet for as long as it takes to fill your tank back up. That's plenty of time for us to get a good soapy hand wash. I've usually dried my hands and left before it stops running.

Please consider buying one of these to help clean tap water stretch further in your area. Water is becoming a scarcer resource as our population grows and demand increases. Sometimes it takes some pretty extreme measures to gather and divert enough water from our wilderness to support humans. Damming valleys, diverting rivers, and draining lakes isn't good if you enjoy the outdoors.


And saving a bit on your water bill is nice too. This is an easy way to do so. As an added bonus, everyone who comes over to your house and sees this thing will get a kick out of it.


Pros: great water saving tool, fun to use

The Sink positive was one of the first products we had on Green Home and finally getting to install and use one was a treat. You don't quite realize how much water 1.6 LPF is until you watch it flow through a faucet...2 people are able to easily wash their hands on one's shocking.


If there is any complaint it's that it splashes a little bit of water around, but that's a small price to pay if you ask me.


The installation was very fast, and if we had figured out that we needed to cut the drain pipe sooner, it would have been over in 90 seconds. Great product.


Great concept.  If money were no object, I'd use these things everywhere -- it's a great way to reduce water consumption.  Leaning over the toilet to wash feels a little awkward, but I'm sure you'd get used to it.  And hey, if you can cut down your water usage by a couple of gallons a day, a little inconvenience is well worth it, right?


The $130 price is a bit steep though, especially considering it's just a molded piece of plastic, a simple faucet, and a couple of hoses.


Pros: Really easy to install, so much water gets reused!

Cons: Splashes a little, a tad awkward to stand over the toilet to wash your hands

Yeah, you think I'm joking but I'm not.  The Sink Positive is so cool.  Deej and I just installed one.  It probably would have taken even less time had we actually read the instructions.  But it's not very complicated.  All you do is turn off the water, take off your existing lid, unplug the tube that goes from the water source to the toilet overflow pipe, twist in the faucet bit to the Sink Positive lid, pop on some tubing, connect a tube here and there, batta bing batta boom, you've got yourself a greywater system!


Helpful hint on installation: They mention this on the instruction sheet (which we read part way through after we realized the sink was about to overflow the first time we tried to use it), but each toilet is a little different in terms of size.  You need to make sure that the tubing that goes from the drain hole on the sink into the toilet overflow pipe isn't bent or hitting the bottom of the pipe.  If it is, the water in the sink won't drain into the tank quickly enough to shut off the water and you'll end up with something of a waterfall going down the front of your toilet.  We cut about 1 and 1/4" off the bottom of our tube and that solved everything.


The flow from the faucet is really quite strong and nice and provides PLENTY (more than plenty) of water for you to wash your hands.  In fact, with one tester flush, Deej and I were both able to wash our hands.  It was crazy.


Another quick note on the design, I'm a fan of the fact that there's a little dish area for a bar of soap built into the left hand side of the lid.  You can also set a thing of liquid soap on the sink extender to the right hand side (depending on the size of your toilet tank).  You can see how we've got ours set up in this action shot.


You do have to bend over the toilet a little, or maybe straddle it if you prefer that.  So that's a tad awkward, but once you get used to it, it's cool.  There is also a little bit of splashing if you're an "active hand washer" because (at least on our toilet), the water comes out with a good amount of force and it's a small sink.  So if other folks are in line after you, you may just have to let them know you didn't miss the toilet's just water.  Or else just take a little more time and be a little more gentle on the ol' paws.  Then you really just have to watch out with dripping when you move your hands away from the sink to where ever you've got your hand towels.


All in all, it's awesome.  I'm thoroughly pleased.  It's a tad pricey (the $129.95 is plus S&H)...but hey, good karma and water conservation are worth it.




Pros: No need to go to the bathroom or kitchen any more

Cons: Didn't work on my french toilet

I bought one of these while travelling, having used it by friends.  It was very very useful, and I wanted the same at my home !!!
Unfortunately, I wasn't able to install it on my (french) toilet : mecanisms into the tank were soooo different from the one supposed to be in for dealing with sinkpositive.
So, I had to look for another one in my country : the WiCi Concept product (see ) appeared to be more expensive, but I was able to install it on my toilet, and it also provided more functions (automatic faucet, soap dispenser).


Pros: Easy to install, very simple to use, saves water

Cons: Slightly expensive for the quality

I love this product. It was very easy to install and is easy to use. What a great way to reduce water use. You could potentially eliminate bathroom sinks all together. I got one for my niece and nephew and not only is it the perfect height for them, it reminds them to wash their hands after using the toilet and to think about saving water.

My only negative comment is that it is made of rather flimsy plastic (it does adjust to fit your toilet tank) and expensive for what a basic product it seems to be. I still recommend it to everyone and think it is a great idea.
Environmental Designworks Sink Positive Tank Lid Sink

This patented multi-purpose accessory sink simply retrofits to your toilet’s existing plumbing in minutes without special tools or a plumber. Starting and stopping automatically after each flush, Sinkpositive will amaze you with how simple and practical a product this is! Quality two piece porcelain-like formed plastic, comes with standard aerator or deluxe aerator tip spout for smoother more gentle water flow. Includes installation instructions and necessary tubing.

Additional FeaturesAerator tip spout
Greywater Source(s)Handwash water
Water ReuseToilet flushing
States Legal for UseAll
Amount of Water Reused2,100 gallons per month (for the average family of 4)
Release Date
Model Name/TypeMPNEAN/UPC

How to Install:



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