Dual-flush toilets

Dual-flush models save even more water

Dual-flush toilets, while mandated in Australia and Singapore, have gained popularity in North America. The dual-flush toilet, a technology first developed in the early 1980s, takes water efficiency one step further by using 1.6 gallons of water to flush solid waste but only 0.8 gallons to flush liquid waste. The two-piece Caroma Caravelle 305 (*Est. $400) has a round bowl (the similar Caravelle 305-EL has an elongated bowl). You control the flush with two separate buttons, and the buttons have raised patterns on them so you can identify them in the dark. The Caroma toilet can save an extra 25 percent water over a standard 1.6-gpf toilet.

While reviews say the water savings is great, and power is good, very little water actually stays in the bowl. Some owners comment that this makes cleaning a hassle, and that because all solid waste doesn't always land in the water, odor can be an issue.

The Mansfield EcoQuantum 147 (*Est. $310) is another dual-flush toilet. This model has an elongated seat. Variations include a model with a round seat, the Mansfield EcoQuantum 146 (*Est. $300), and an ADA-compliant version with a high seat, the Mansfield EcoQuantum 148 (*Est. $340). In tests, the Mansfield dual-flush toilet outperforms the Caroma Caravelle by a bit. Downsides are that it can be noisy, and because of the low water level, it has the same cleaning and possible odor drawbacks as other dual-flush toilets. Good luck finding these toilets, however. They are not available in the big-box home-improvement stores, but can be found online (primarily at Vidavici.com).