Culligan offers faucet-mounted, under-sink, refrigerator, shower massager, standalone, and whole-house water filtering systems. It even has water filters for recreational vehicles (motor homes) and boats. Culligan has do-it-yourself water filters and professionally installed and serviced water filters; cartridge and cartridge-free (nothing to change every few months) water filters; activated charcoal, reverse osmosis, and combination water filters.

By now, you may have formed the impression that Culligan has too many water filters! Relax; the right product is what the Culligan Man is paid to figure out for you. All you need to do is take a good look at your water; and taste, smell, and feel it. Then go to the Culligan Web site and answer its multiple-choice Needs Assessment survey.

Notice that all survey answers lead to one of two action recommendations: "contact local health department" or "contact your Culligan dealer". See? It is simple!

Culligan is the only water treatment vendor I've seen that tells people what to do when it can't sell them something helpful. It's kind of like that car insurance company that shows you other companys' rates even if they're lower.

Culligan's reverse osmosis system is an advanced water filtration technology not found in faucet-mounted or pitcher-mounted water filters, or in many under-sink and refrigerator water filters. In reverse osmosis, high pressure is applied to raw tap water, forcing the water through a semi-permeable (partially penetrable) membrane. The membrane is called "semi-permeable" because its microscopic holes allow water to pass through, but not most other materials that are dissolved in the water.

Other water filtration systems can't remove as many solutes (things dissolved in water) as reverse osmosis water filters. Pleated "paper" filters have holes much larger than those in semi-permeable membranes, allowing many organic chemicals (such as pesticides and petroleum products) salts, metals, and other solutes through. Activated charcoal is also less effective at removing salt and metal solutes.

The downside of reverse osmosis includes wasted water, and lower water pressure at the point of use, and higher energy costs. About 75% of the water that enters a reverse osmosis system carries solutes down the drain; in other words, it can take four gallons of tap water to make one gallon of filtered, usable water by reverse osmosis. Filtered water is stored in a tank whose valve flows more slowly that your regular faucet. The smallest bacteria and viruses are not removed by reverse osmosis. Unlike passive filters, reverse osmosis uses energy to generate the high pressure that makes it work. So, one’s water and electricity bills will be significantly higher with a reverse osmosis water filtration system.

A whole-house water filtration system is convenient; one water filtration system provides purified water to every outlet in the house. There is only one filter to change, and one filter-changing schedule to keep track of. A whole-house water filtration system is out of the way, discreetly hidden in the basement near your home's main water tap. A whole-house water filtration system is costly, but its initial purchase and ongoing maintenance costs may be lower than having water filters on every water tap and toilet in your home.

The biggest health and safety concern with whole-house water filtration systems is the plumbing between the point of filtering and the point of use. If your in-house pipes are corroded, or made of lead, or contaminated with bacterial or fungal growth, then purified water may become contaminated by the time it flows out of the faucets.

Culligan offers a daunting variety of water filtration options. But the company also offers free, professional services to help you choose the water filtration system that's right for you.