Installing Operating
your Model 77 Countertop Filter

Thanks for buying our Model 77 Countertop water filter. It's a product we're proud of, and for a long time we've been calling it “the world's greatest $77 water filter.”

The following pages tell you how to install it, how to use it, how to maintain it, and how to get it fixed if anything goes wrong. You'll like its easy-to-service features (you should never have to send it back — you can easily do any repairs yourself), the low cost of operation, and the fact that it has an absolute 100% lifetime guarantee.


To install, unscrew the aerator from your sink faucet and attach the filter's diverter valve in its place. If it doesn't fit, use one of the enclosed adapters. The diverter valve will fit most faucets without an adapter, and the enclosed adapters will attach it to almost all others. For faucets with an unusual thread pattern, consult a good hardware store, or feel free to call us.

To operate the filter, turn on the cold water to a moderate flow rate, pull out the diverter valve stem, and water will eventually begin to flow through the filter. For initial operation, let the water run for four or five minutes before drinking. When the faucet is turned off, the valve stem will pop back into place and allow normal use of the sink faucet.

Do not run hot water through the filter.

Note: It may take as much as a day for all trapped air to work out of a new filter cartridge. If water dribbles from the end of the spout after the inlet water is turned off, or if water appears cloudy, the problem is trapped air. It will correct itself, and in the meantime, the water is safe to drink.

Servicing your Model 77 Water Filter

Servicing a Model 77 consists mainly of changing its filter cartridge once a year. We have a record of the cartridge that was original equipment in your water filter and can ship it to you if you don't know its name or model number.

To replace the cartridge:

  1. Open the filter by screwing the tower off of the base. It comes apart at the base and it's a standard thread pattern that loosens by turning left. It isn't practical to use a wrench on a countertop, so just muscle it apart. If you can't get it open, the best strategy is to get someone to help so that each person can use both hands. One person holds the base while the other screws off the tower. Sometimes units that have been in use for a long time are hard to open. If you can't get it, call us. We know some tricks that work.

  2. While the unit is open, it's a good idea to lubricate the black O-Ring that's in the groove of the tower of the filter vessel. Lubricate lightly with silicone grease, if you have some, or Vaseline if you don't. Silicone won't cause the O-Ring to deteriorate. Lubricating the o-ring will make the unit come apart much easier when you service it next year, and it's much less likely to leak.

  3. Replace the cartridge. With open-end cartridges like the standard carbon block cartridges, there is no “up” or “down”. Put it in either way. With “Media Style” cartridges, or with any closed cartridge with a plugged end, it will only fit the right way. If it goes in, you've got it right. Don't force it. With the candle style units, you screw the threaded portion into the only place it will screw in, no way to go wrong on these — but don't over tighten, just get it snug. With standard cartridge models, it's very important that the end gaskets don't fall off or get out of place during installation. The unit won't work properly if the end gaskets can't make a tight seal.

  4. Reassemble by screwing the vessel back together. If the o-ring is lubricated, just get it hand tight. Most leaks occur because the o-ring buckles or is pinched when it is tightened. If it leaks, you can always tighten it a little more.

  5. After the unit is reassembled, run water through it to check for leaks. Allow it to run for a few minutes to rinse the new cartridge before using the water.


Model 77 is designed to be trouble-free. However, diverter valves, no matter how good they are, sometimes become clogged with minerals from the water and begin to stick. The best regular maintenance you can do is to remove the diverter valve from the faucet about once a month and drop one or two drops of vegetable oil into the small hole where water enters the valve. Work the stem back and forth until it moves freely. This will add years to the life of the valve and ensure smooth, trouble-free operation.

Leaks at fittings are rare and can usually be corrected by tightening the fitting or wrapping the treads with teflon tape. If the unit leaks at the bottom where the tower screws to the base, be sure the O-ring in the tower is in place and screw the pieces together firmly. At annual cartridge change, lubricate the O-ring lightly. Silicone grease is the preferred lubricant, but petroleum jelly will work.


All parts of the Model 77 Countertop Water Filter (and our Double Countertop Filter) are guaranteed for one year from the date of purchase. Any part that fails within this period will be replaced without cost for parts, labor, or shipping. The single exclusion from this guarantee is the replaceable filter cartridge.

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