Portland water and sewer rates are very, very high. They are the leading expense in my rental units. I have Drakes now, but am thinking of putting in Niagra's to cut the flush in half (0.8 gallon versus 1.6). But that seems awfully low. I know Niagra from their showerheads. From outward appearances, it looks like they may source the toilet from a third party (probably in China unfortunately) and just supply the "guts." Am looking for any feedback on how effective they are and how wise an idea this may be.
Why not wait just a smidge and see how Terry's full experience is with the new Toto 1.0gpf model. Chances are that it will work well and be easy and inexpensive to fix.
Of course, when you have rental units and the tenants get their water for free, I wonder what percentage of use the shower is vs. the toilet? Are their any studies by the landlords' associations on how much total water consumption goes down from replacing a toilet? Of course, you may be eligible for some rebates to make that change more palatable. Also, if the water consumption gets so low that the toilet flushes but a line downstream gets blocked from not having enough water to "wash it down", then you may be trading one expense for another. That would be another thing that might be worth having a landlord's group study...
EDIT: I actually did some research to see what was out there on these questions and the financial viability of attempting to reduce cost by replacing 1.6 gpf toilets with the one you're thinking about. Here's what I found: A marketing piece from TOTO about their 1G (1 gpf) toilet estimates that the average American flushes 5 times per day at home, and then does some extrapolating based upon an average family size of 3.2, and estimates that 3.2 users of a 1.6 gpf toilet flushing 5 times per day would burn through 9433 gallons of water flushing in a year. So let's back out the 3.2 and give you a number per-tenant, since only you know how many tenants on average you have in a unit. So each tenant uses 2947 gallons of water per year flushing, assuming the American average of 5 flushes per day. By replacing all your 1.6s with 0.8s, the best you can hope to save per tenant, then, is 1474 gallons per year, and this assumes that the 0.8s don't give the tenant any incentive to do a second flush. (I would round these numbers because being this precise about flushes seems a little silly, but we might as well leave it at this level of detail for now.) So that's the maximum water savings per tenant. So what does that translate to in dollars. Well, the best I can tell from the Portland City web site is that the retail water and sewer combined rate for retail inside-the-city-limits water customers is $3.086 per 100 cubic feet of water. Portland seems to add all sorts of wacky fixed charges that drive up the monthly water bill, but $3.086/100 cu ft. seems to be rate for actual consumption, which would seem to be the only thing you can affect by reducing consumption. If I'm wrong about this, then whatever charges also vary with consumption can be factored into my math here. 100 cubic feet of water is 748 gallons, so the variable retail price per gallon is [3.086/748 or] $0.004125. So, if you save 1474 gallons per year, you save $6.08 per tenant per year. If you have an average of 2 tenants per apartment, then you might save $12.16 per year. If you have one toilet per apartment, then your payback on the $308 investment would be about 25 years. If you have four tenants per apartment, then the payback period is cut to 12 years. If there are additional variable charges I am not considering, then YMMV, but I do note that Niagara itself estimates $4/1000 gallons as the water price in their examples, which is consistent with the numbers used here. The good news about your Stealth is that it is about half the retail price of what Toto is publicly estimating for the 1G, which I guess for now will be a high-end model, although I imagine that the technology, if successful, will filter down as it always does. BTW, Niagara seems to think that going with a 1.25gpm showerhead will save twice as much water than their toilet, as well as some electricity, and they only cost $19.95. Of course, the savings assumes that the tenants don't claw them off the wall and replace with a higher-flow version, but still it seems like a more obvious path to money savings (and water savings).