The most important factors to consider when purchasing a toilet are the type and water usage, according to Consumer Reports. The two types are gravity-feed toilets that pour water onto waste to force it down and pressure-assisted toilets that use water to displace air in a sealed tank, creating a vacuum effect that forces waste down. Water usage is identified by two features: WaterSense-certified toilets that use 1.28 gallons per flush and dual-flush models that have the option of half-flushing.
Gravity-feed toilets comprise about 90 percent of all toilets sold in the United States, according to Consumer Reports. They are much quieter than pressure-assisted models and require less water pressure in order to function, needing only 10 pounds per square inch versus 25 for pressure-assisted models. The best of them are as effective as pressure-assisted models as well, but they tend to cost just as much. Lesser models may not be up to every job. Pressure-assisted toilets noisily announce each flush, but they generally get the job done.
The U.S. government requires that all toilets manufactured after 1995 use 1.6 gallons of water or less per flush as of 2015. California has a stricter water conservation law that limits the threshold to 1.28 gallons, with compliant models gaining WaterSense certification. Dual-flush models half-flush liquid waste, saving water while maintaining the ability to eliminate solid waste with a full flush.
Price point was not a major factor in Consumer Reports' field tests, as the best toilets carried only a midrange price tag. Other options include bowl height, color, bowl shape, concealed trapways and two-piece designs. Consumer Reports subscribers can access a bowl by bowl performance breakdown, but the organization does not make this information publicly available, as of 2015.