How To Install A Multipure Water Filter Under The Sink?

A Multipure water filter
A Multipure water filter

A Multipure water filter is a filtration system used to improve drinking water quality by removing contaminants and impurities. It uses a multi-stage filtration process that includes activated carbon, ion exchange technology, sedimentation, and reverse osmosis. This process helps to remove things like chlorine, lead, viruses, bacteria, pesticides, and other contaminants that can affect the taste and safety of your drinking water. Multipure filters are certified by NSF International, a not-for-profit organization focused on public health and safety standards. Installing a Multipure filter is relatively simple, although it does require some basic plumbing skills.

Tools Required For Installation

Tools Needed
Tools Required For Installation
  • 3/8″ Reversible Electric Drill
  • 7/16″ (or 1/2”) high-speed steel drill bit
  • ½” carbide-tipped masonry drill bit
  • Hammer
  • Center punch
  • 8″ adjustable wrench
  • Pliers or Vise Grips

How To Install A Multipure Water Filter Under The Sink?

Drill the hole: Begin the installation by drilling into your sink’s cabinet wall. Note where existing plumbing and electrical wiring are located and use caution when drilling.

Install the faucet: Turning off the water supply line below the sink and disconnecting the hot and cold lines from the existing faucet. Once this is done, insert your new Multipure faucet into the hole where your old faucet was and tighten the mounting nut from underneath.

Mount the faucet: Begin by attaching the faucet to the sink or countertop. Make sure to attach it with a firm grip so it won’t be loose. Use caution when drilling and follow manufacturer instructions when mounting the faucet.

Connect the tubing: Once you have the filter in place, you will need to connect the tubing. Take the tubing that came with your multipure water filter and attach one end to the outlet on the filter and the other end to a cold water supply line under your sink. The connection should be secure, so use plumbers’ tape to ensure it won’t leak.

Connect housing: Attach the housing to the sink or countertop hole using the nut and washer provided. Ensure that a tight seal is achieved by hand tightening until it is secure. Make sure not to over-tighten, as this may damage the threads.

Connect the adapt valve: Once you’ve got the filter in place, it’s time to connect the adapt valve. This will be the primary connection between your plumbing system and the filter. Put some thread sealant onto the threads of the adapt valve before connecting it to ensure that it is sealed tight and will not leak. If you have additional fittings, such as a shutoff valve or a hose bib, attach them to the adapt valve before tightening it.

Connect the Fittings to the Housing:  Attach the 3/8-inch brass nut to the threaded end of the cold water supply line. Insert the compression sleeve into the other end of the cold water supply line and thread it onto the adapter fitting on top of the housing. Secure with a wrench if necessary. Connect the 1/4-inch plastic tube from the faucet adapter to the other end of the adapter fitting on top of the housing.

Connect Tubing to the Outlet Port: Attach the 3/8 inch copper tubing to the housing outlet port. Secure with a wrench and ensure there are no leaks. Connect the other end of the copper tubing to the cold water supply line from your faucet adapter. Again, secure everything with a wrench and ensure there are no leaks.

Connect Tubing to the Inlet Port: Connect the provided tubing to the inlet port on the underside of your Multipure water filter. The inlet port is typically located at the top of the side or back of the unit and should have a small arrow pointing towards it to indicate which way is up. Line up the ends of both tubes so that they are even, and firmly push the end of the tube onto the inlet port.

Mount the System Under the Sink: Mount the system under the sink and connect the faucet adapter to the cold water line. If a diverter valve is included, it should be installed first before connecting the filter. The diverter valve will control when water flows through the filter or bypasses it to flow directly from your incoming water line. Attach one end of the flexible hose to the diverter valve and the other to the filter mount. Attach the filter cartridge to the mount.

Replacing The Multipure Water Filter

Step 1. Turn off the water supply: Shut off the main water valve and ensure all faucets are turned off.

Step 2. Disconnect existing filter housing: Unscrew any fittings connecting the current filter housing to the sink, faucet, or pipes, then remove the housing under the sink.

Step 3. Install new filter housing: Place the new filter housing in the same spot as the old one, then screw any fittings back into place so that it is securely fastened.

Step 4. Connect hoses to the multipure filter system: Attach one end of the hose supplied with your new multipure filter system to the filter housing and the other to the faucet.

Step 5. Open water valves: Turn on the main water supply valve and check all connections for leaks. If there are no leaks, turn on each house faucet to out any sediment or particles that may have been left in the system.

Step 6. Replace filter cartridge: Once the water is clear, unscrew the top of your multipure filtration system and replace the old filter cartridge with a new one. Once securely, screw the cap back on and turn all faucets off.

Step 7. Leakage test: Turn on the faucet and check all connections to ensure no leaks. If everything is secure, your multipure water filter system should be ready for use.


Bypass lever – stuck: If the bypass lever on your Multipure water filter is stuck, you may need to reset it. To do this, gently push down on the handle and rotate counter-clockwise until it unlocks. If this does not work, a professional may be needed to repair or replace the affected parts.

Rotten egg odor: If you notice that your tap water has a rotten egg odor, this is a sign that there may be sulfur in the water. Installing a Multipure filter under the sink is an effective and easy way to reduce sulfur levels and eliminate odors in your drinking water.

Flow rate is slow: If you find that the water flow rate is slow after installation, you can take a few steps to troubleshoot.

  • Make sure all connections are correctly fastened and secure. Check for any kinks in the tubing or filters that might block the water flow.
  • Make sure there is no air trapped in the system, as this can slow down the flow. If the water pressure to your sink is low, it may be necessary to install an auxiliary pump to increase performance.


Does the filter work for biological contaminants such as e coli?

Yes, the Multipure water filter can effectively remove bacterial contaminants such as e coli. The NSF/ANSI-certified carbon block filters used in our systems are specifically designed to reduce microbial contaminants like e coli.

Does the filter come with the kit?

Yes, a multipure water filter comes with the kit. It will include all the necessary parts and equipment to install the filter, including a shut-off valve, mounting brackets, mounting screws and washers, tubing, clamps, faucet adapter, and cartridge.

Should sediment be removed with a standard filter first?

Yes, sediment should be removed with a standard filter first. This is important for the quality and life of your Multipure water filter system. Sediment can clog up your filter and reduce its filtration effectiveness over time. Installing a sediment pre-filter can help prolong the life of your Multipure filter system and ensure its optimal performance.

Can the multi-pure system be used on untreated water?

Yes, the multi-pure water filter can be used on untreated water. Whether your water is city or well-sourced, you’ll need to ensure that it meets all applicable regulations and standards before installing the multi-pure system. The system needs a minimum pressure of 25psi (172kPa) and a maximum pressure of 100psi (689kPa). It is important to note that the system will not effectively remove all contaminants from your water if it does not meet these standards.

What is the difference between a “water softener” and a Multi-Pure Drinking Water System?

The Multi-Pure Drinking Water System is a point-of-use (POU) filtration system that eliminates contaminants from water at the source. It does not soften the water, as a water softener would. A water softener works by exchanging calcium and magnesium ions in hard water with sodium or potassium ions, resulting in softer, less harsh water.

Will low pH or acid water affect the Multipure filter?

No, the Multipure filter systems are designed to handle a wide range of pH levels, from 3-10.5. The water filters come with built-in resistance to acid and alkalis, so you don’t have to worry about them being affected by the pH level of your water supply.

Can the Multi-Pure System be connected to an automatic ice-maker?

Yes, the Multi-Pure System can be connected to an automatic ice-maker. The Multi-Pure Point of Use System should be installed downstream from your ice maker to protect your system from any potential damage. This will ensure that water is filtered before entering the ice maker and prevent scale buildup caused by minerals in untreated water.


Installing a Multipure water filter under the sink is an easy process that can be completed in less than an hour. The installation will require essential tools, such as wrenches and pliers, but they can easily be found around the home or purchased at a local hardware store. Once installed, having clean, safe drinking water right from your tap can be a great convenience and save you money in the long term. With a few simple steps and essential tools, you can easily install a Multipure water filter under your sink for clean, healthy drinking water.

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