• Compare the water filter ratings from several sources.Michael Blann/Digital Vision/Getty Images
  
  Several websites and periodicals provide reviews and comparisons of various water purifiers, generating a wide spread of winning filtration systems. While many publications compare the efficiency and value of various filters, the diverse range of models available prevent any single best-rated model from standing out above the rest. When weighing the ratings of various filters, you also need to take into account the filter's design -- whether faucet-mounted, under-sink mounted, countertop or in a pitcher style.
  
  

Clear 2O

• Both Good Housekeeping and Consumer Reports magazines have praised the performance of the Clear2O water filter. According to Good Housekeeping's editors, it ranks as one of the top eight household products you can buy. According to Consumer Reports, the Clear2O is the best buy, scoring just two percentage points lower than their top-scoring model but costing just one-fifth the price. Consumer Reports describes the pitcher's flow rate, chloroform and lead removal properties as "excellent" and its resistance to clogging as "very good." Good Housekeeping points out how favorably the flow rate compares with water straight from the faucet. In addition, it praises the Clear 2O's large capacity.
  
  

Everpure H-300

• The Green Guide, National Geographic's online collection of reviews, recommends the Everpure H-300 among the seven models they compare. The trial takes into consideration the filters' ability to remove major contaminants. It only used products certified by the National Science Foundation and designed to treat small amounts of water at a time. The Everpure H-300 mounts under the counter and uses a carbon-based filtration system. Among the seven filters tested, it's the second most effective at removing contaminants, bested only by the Pur Horizontal FM 9400, a faucet-mounted model. According to the trial, the Everpure's price is comparable to other under-sink models, including the Kenmore Elite 38556 and the Aqua Pure by Cuno AP-DWS1000.
  
  

Pur 2 Stage 7 Cup Oval Pitcher

• National Geographic's Green Guide gives the Pur 2 Stage 7 Cup Oval Pitcher a top rating as the "best value" among the seven filters it tests, making it an ideal option for the budget-minded consumer. Among the entries for the testing is the only model with a carafe design. The Pur 2 Stage 7 Cup Oval Pitcher uses a carbon filter like the majority of the filtration systems in the trial. It is certified to remove 8 different contaminants, on the lower end of the spectrum among those that Green Guide tested. The price reflects the pitcher design, much less expensive than any under-sink mounted models and comparable to faucet-mount designs.