Toilets don't normally come up in conversation. The last time they were in the news was back in 1997, when the federal government passed a law requiring that all new toilets use a maximum of 1.6 gallons of water per flush. The new requirement generated loud complaints on editorial pages about government overreaching, and the slew of poorly functioning toilets that ensued gave comedians some good punch lines. In fact, a little research at the time showed that government was being falsely maligned, and that a few unsung manufacturers responded to the regulatory challenge by designing effective toilets.
In searching for a replacement for the old, inefficient 4 gallon toilets in my house (3 gallons if one puts bricks or weighted bottles in the tank), it turns out that manufacturers have figured out how to use even less water than the government standard. Toto has come out with a 1.28 gallon toilet, and I've been told by a local retailer that all manufacturers will be using less than 1.6 gallons in the future. There are also duel-flush toilets, which have a 0.8 gallon flush for liquid waste, though these are more expensive. We bought a 1.28 gallon Drake with a so-called E-Max gravity flush, which works far better than any of the old 4 gallon types.
Not all regulation is so constructive, but in the case of the lowly toilet, manufacturers responded to strict limits on water consumption by making a better product, and even going beyond what the government required.