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WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
Water filters: this article describes different types water filters used for drinking water purification both as portable filters and where installed on building water supply systems, including both municipal water supplies and private well water systems. The filters described here are usually intended to improve aesthetic issues in home water supply such as removing debris particles, sediment or odors.
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Following the "best filter" introduction just below we describe each of the types of drinking water filters intended for in-home or in-building installation & use.
What is the "Best" Water Filter for Home Water Supply Systems?
There is not a single "best" water filter for home use if you consider that what makes sense is to choose a water filter based on what contaminants you want to remove from the water.
Charcoal filters: charcoal filters are great at removing residual chlorine and odors in drinking water and can also remove sediment and even some pathogens. The U.S. EPA notes that solid-block charcoal filters can remove a wide range of water contaminants including
Watch out: But charcoal can also serve as a pathogen growth media, and these filters can clog rapidly if the water supply is high in sediments. For this reason you'd place a charcoal filter, if needed, downstream from the sediment filter and downstream from a UV light or other disinfection system.
Details are at
Reverse osmosis: is a type of water filtration using a permeable membrane that can remove a very large range of contaminants, though these systems also waste water in the process. Typically we'd precede an R.O. system with a sediment filter to first remove large particulates and/or a charcoal filter to remove odors & residual chlorine.
Sediment filters: visible particles in the water supply are not only unpleasant but as we warned above, they can interfere with removal of pathogens from the water supply. For this reason it makes sense to place a sediment filter ahead of any other water treatment equipment in the building. The size of a whole house sediment filter that you require depends on the water usage rate and the level of sediment in the supply.
Pros/Cons: Advantages and Problems with Various Types of Water Treatment Equipment for Bacterial or Bacteriological Contamination
Technical note: the same clay, silt, or other debris that clogs a water filter
can clog up the pressure sensing opening in the bottom of a pump pressure control switch, as we discussed just above.
The sketch at left shows the basic parts and functions of a typical cartridge-type water filter.
Detailed descriptions of other water system parts and controls, valves, switches, pumps, piping, etc. are provided in the various sections of this article and are listed just below. [click the image at left to see an enlarged schematic of the water filter and its parts.]
Types of Drinking Water Filters
Cartridge Type Water Filters
Water is passed through a filter cartridge that is usually contained in a plastic or metal canister. Both portable and permanently-installed water filters are widely available and form the most common water filter system found in residential installations where sediment, odors, or chlorine residue are a concern.
The sketch at left illustrates the water filter element and the path of water passing through it.
Watch out: most conventional cartridge-type water "filters" such as the filter cartridges shown at left are not water purifiers. Only a filter that is certified to remove adequate levels of bacterial contamination are permitted to be sold as water "purifiers". Typically a filter that functions as a water purifier will be a ceramic device.
Ceramic water filter-purifiers, including hand-held portable units capable of removing bacteria, cysts, cryptosporidium, sediment, and other water contaminants are discussed in detail at CERAMIC FILTERS & Water Purification. We recommend that you review independent water filter performance or water purifier performance test reports before relying on a water filter/purifier for the production of safe drinking water.
Watch out: the functions performed by any cartridge type water filter depend on the material from which the cartridge is made. And many home water filter canisters will accept a variety of filter cartridge types intended for varying purposes.
Be sure to read the properties of the filter cartridge you are buying and select a filter cartridge type that performs the functions required. For example a water filter designed to reduce sediment may work well for that purpose but may be ineffective at removing odors.
Hooking Up a Cartridge Type Home Water Filter - typical plumbing connections
As the water filter parts sketch at left shows, a cartridge type water filter is installed in-line in the main water supply pipe after the water pressure tank and before the cold water line branches off to hot water or other destinations. Shown in the schematic is a standard-sized whole house water filter from Aqua Pure (3M) type AP11T. 
You might want to install the water filter downstream of your piping that feeds outside faucets used to water the lawn or wash cars, as you probably don't need to filter that water stream.
The sketch shown at left is the simplest installation, showing a single shutoff ball-valve on the inlet side of the water filter.
Notice that most water filters are installed with the cartridge/canister pointing "down". The filter would work in other positions but only in this down-position can you unscrew and remove the filter base to change the cartridge while avoiding spilling an unnecessary dose of dirty water on your floor.
Most water filters including the water filter shown at left include a shutoff or bypass built into the filter head. The water filter shown at left was installed ahead of a UV light water treatment system. In that location the water filter helps keep the UV light bulb clean and improves the both the level of UV treatment (for bacteria) and reduces the frequency of the need to change-out or clean the UV bulb.
You can see the plastic water filter body wrench in our photo (yellow arrow). We hang this tool near the filter where it won't get lost.
With the filter "off" or on "bypass" you can unscrew the plastic filter base to change the filter cartridge without having to use other water shutoff valves. But we like to install the water filter with more options, as shown in our photo. Most plumbers will install two shutoff valves at the water filter:
Shutting Off the Whole House Water Filter - by Valves or the built-in Bypass/Off Control
Closing both of these valves allows complete removal of the whole water filter assembly without spilling water from the building piping and water supply system should the filter assembly need to be changed out.
A third shutoff valve on a bypass loop that can, if this valve is opened, completely bypass the whole water filter installation. This plumbing bypass around the water filter is handy if the unit is damaged, leaky and needs complete replacement.
To make it easy to change the water filter cartridge most water filters include a built-in shutoff-valve in the plastic filter body top - the red arrow in our photo above and marked by the blue tape in our photo of a Sears whole house cartridge type water filter (photo at left).
This handle rotates to 90 degrees from the position shown in order to turn off water at the filter entry port. Now the cartridge base can be unscrewed, cleaned, and a new filter cartridge installed.
Watch out: Take care when installing the new water filter cartridge that you hold the canister and cartridge upright and that the cartridge is properly seated in the bottom of the canister and that it seats centered in the filter top to which the canister is screwed. If you let the filter flop over to one side during installation the assembly may not filter water and it may even leak.
We like to note the date that the filter cartridge was installed - in the photo we just stuck a piece of blue masking tape on the filter shutoff handle and wrote down the filter cartridge installation date. Then when your water pressure falls to nil and you go to change out the filter cartridge you can embarrass yourself by noting how ridiculously long you'd left the old filter cartridge in place.
Brands of Water Filters used for Drinking Water Treatment
Above at WATER FILTERS, HOME USE we discuss the installation and use of water filters on private water supply systems, a portion of our review of WATER TREATMENT EQUIPMENT CHOICES. Also see WATER ODORS, CAUSE CURE.
Just below we provide the most comprehensive list of water filter and replacement water filter cartridge brands we have been able to find. CONTACT us to add to this list. These water filter products are available from building suppliers, plumbing suppliers, hardware stores, and on-line.
Purchases: With the exception of links to recommended books at Amazon.com who pays us a microscopic commission on book sales, we do not sell anything. Please do not call or write asking to buy something.
American Plumber Replacement Filters American Plumber Filters
Readers concerned with water purity or water potability should also see Filters for Drinking Water Purification for a discussion of portable and emergency water filters that are designed to purify drinking water, including portable ceramic water filters, silver ceramic filters, magnetic (bogus) water purifiers, paper and polypropylene water filters, etc. See WATER TREATMENT EQUIPMENT CHOICES for details on other water treatment options besides filters.
See DRINKING WATER EMERGENCY PURIFICATION for a discussion of various methods used to purify emergency drinking water. A companion article, DRINKING WATER EMERGENCY SOURCES,describes possible sources of drinking water that may be useful in emergency conditions. For explanation of the different types of water treatment systems used on building water supplies, see WATER TREATMENT EQUIPMENT CHOICES.
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Frequently Asked Questions (FAQs)
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Question: how do I find a water filter that can withstand my house water pressure range?
I need to buy whole house water filter with max pressure 20-100 psi .
It would be very unusual for a home water system pressure to exceed 70-80 psi and unusual for a home water filter to be unable to withstand that pressure range. As an example,
Frankly you should never see home water pressure operating over 75 psi - as higher pressures make for leaks and risk other damage.
It is quite easy to measure your home water pressure both static (when no water is running) and dynamic (when water is turned on at one or more fixtures) by using a home-made or store-bought water pressure gauge. See WATER PRESSURE & FLOW MEASUREMENT
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