6 Reasons To Switch off Your Water Purifier Everyone Should Know!

Most people in the U.S have a water purifier or filter at home, and many wonder if they can (or should) turn them off at some point. While most water purifiers can be switched off, it depends on the type of water purifier.

Distillation, Reverse Osmosis, Ultrafiltration, and Ultra Violet water purifiers can all be switched off. Home water purification systems can (and should) be switched off during installation, cleaning, freezing water temperatures, hot water flows, low water supply periods or when going on vacation. Water purifiers should not be switched off at night.

Deciding when and how to turn a water purifier off depends not only on what type of water purifier you have, but also how it purifies water. So, keep reading for all the information you need, to know when and how to switch of YOUR water purifier.

Can a water purifier be switched off?

Some home water purification systems can be switched off – but it depends on how they purify water.

Distillation, Reverse Osmosis (RO) and Ultra Violet (UV) water purification systems that use electricity can be switched off. For some of these systems you may just have to flick a switch, while others (e.g. distillation) you will need to unplug.

Ultrafiltration (UF) water purifiers do not actually use electricity, unless of course you have a booster pump. If so, that extra water pressure means you will probably want to turn off your UF water purifier while you are away, and luckily you can.

Gravity-based purifiers use sediment, charcoal and carbon filters to treat water, but do not use any energy. Because of this they cannot actually be turned off. However, if you remove the system’s water supply the water purifier will stop running.

Faucet-mounted filters do not use electricity either, but can actually be turned off. This means you can choose when to use filtered or unfiltered water.

Here is a list of the different types and methods of water purification, and whether they can be switched off or not:

Type of water purifierMethod of water purification Can it be switched off?
On-counter (counter-top)Gravity
Reverse Osmosis

Under-sinkReverse Osmosis
Ultra Violet

Whole-houseReverse Osmosis
Ultra Violet

Don’t forget – in general you should not switch your water purifier off at night. Even if it is to save a bit of electricity or wear and tear on the unit. Water purification systems are made to operate almost continuously and switching them on or off unnecessarily can damage the parts.

So, perhaps more important than ‘can’ your water purifier be switched off, is ‘when’ should it be switched off ?!– keep reading for the 6 most important reasons why you should be switching it off

6 reasons to switch off your water purifier

Here are the main reasons why you can (and should) turn off your water purifier:

  1. During Initial installation
  2. Cleaning the unit
  3. Heading away on vacation
  4. Freezing water temperatures
  5. Hot water flows
  6. Low water supply

1. During initial installation

Believe it or not, water purifiers often need to be switched off (and on) when you are first installing your system.  This is to allow proper flushing of the unit, and the storage tank in particular, to make sure your water will be safe to drink

2. Cleaning the unit

Every type of water purifier should be cleaned regularly, and almost every type of water purifier should be turned off for cleaning. It is especially important to switch off water purifiers before cleaning the storage tanks of UV and RO systems or the boil chamber of a distiller.

3. Going on vacation

If you are heading away on vacation for even a few days, you should switch off your water purifier. In fact, Eureka Forbes advises switching off your water purifier

“if it will not be used for more than 3-4 days”.

If you leave your water purifier on and idle while away, the filter components can become damaged and the wastewater stagnant! But, more importantly bacteria will start to grow in the unused water, making it undrinkable!

4. Freezing water temperatures

Water purifiers should never be exposed to water that is near freezing. Manufacturers such as Apec and Forbes recommend that feed water should never be below 40 degrees Fahrenheit. Unfortunately, this means during those cold winter months you may have to switch off your water purifier, at least until the water warms up again.

5. Hot water flows

Just as water purifiers should not be exposed to near-freezing water, nor should they be exposed to hot water flows. Most manufacturers advice is that feed water should never be above 120 degrees Fahrenheit.

Hot water flows damage the filters and membranes of all water purification systems. This includes faucet-mounted filters, and is why you are able to switch them off – so that you can still have hot water flow through your taps! So always remember, if it is hot water that you want – switch off your water purifier!!

6. Low water supply

Low water supply to your water purifier means low feed water pressure. Water purifiers have an optimal operating pressure range for feed water, but every type of water purifier has a different range – which makes it confusing!

For example some reverse osmosis systems cannot operate with tap water pressures below 40psi, while some faucet-mounted filters can operate with water pressure at 20psi, and some UV purification systems as low as 9psi.

Make sure to ask the manufacturer of your water purifier what your optimal pressure range is, so that your purification system keeps on working!

How to turn your water purifier off

How to turn your water purifier off will depend on what type of system you have. Check out the most common types below, and how to turn them off!


  • For small units – Simply unplug the power cord from the wall to turn the unit off!
  • For large automatic units – Just turn the power switch off.

Don’t forget that most counter top distillers have a thermostat that will shut the unit off at the end of the cycle – so your purifier may look like it has been switched off but may not be!

Faucet-mounted filters

Most faucet-mounted filter have a lever that you turn to get filtered water, so by simply not turning the lever, your filter remains switched off. But, if you need to change your filter or remove it from your faucet don’t forget to turn off your main water beforehand!

Reverse Osmosis

  • Turn off the feed water valve – this is usually perpendicular to the cold water line
  • Drain your system by opening the RO faucet – water will empty until the storage tank and filters are empty
  • Turn off the valve on top of the storage tank – this is usually perpendicular to the tubing when switched off.

Ultra Violet

  • Turn off electrical power to the water purifier
  • Turn off the water supply at the point of entry

Remember most UV water purifiers are made to run almost continuously, so don’t turn your UV bulb on and off unless you need to turn the whole system off. Otherwise you can shorten the life of your bulb!


Steps to switching off you ultrafiltration system will vary depending on the size of your unit but here are some general steps to manually shutting off a large one:

  • Turn off the main switch on the control panel
  • Turn off:
    • Feed water inlet
    • Feed water pump suction
    • Feed water pump discharge
    • Purified water pump suction
    • Purified water pump discharge
    • Purified water outlet
  • Open the drain!

How do I know if my water purifier is working?

Unfortunately there is no way to really be sure that your water purifier is working, and decontaminating your water supply.

Contaminants affect water differently – some make the water taste bad, while others change the color of the water. But, other contaminants are not so easily discovered – this makes it extra important to always follow the operating instructions of your water purification system.

Regular cleaning, maintenance and filter changes are the best steps to keeping your purifier working!

Don’t forget you can always test your water before and after it is purified to see if it has, in fact been purified – This is a simple way to confirm your water purifier is working.

Do-It-Yourself water testing kits are cheap and super easy to use. I recommend this test from Amazon because it checks for 20 contaminants and you don’t have to be a scientist to figure out the test! It can even detect bacteria and pesticides – which most other tests don’t.

Amazon affiliate image link

You can also send a sample of your treated water to a state certified lab if you want to be sure that your water purifier is working. Although, it is a more expensive option.

If you are still concerned about your water quality take the time to check if the National Sanitation Foundation (NSF) has certified your purifier. Here is the link to their list of certified systems.

For more information about why your water filter may not be working and how to fix it check out this detailed post.

Related Questions

What is the auto shut off in a Reverse Osmosis water purifier? The auto shutoff is a valve that automatically switches off the feed water flowing into the reverse osmosis system when the storage (reserve) tank is full. Without the auto shutoff, purified water would be pushed down the drain once the tank was full.

Do you have to shut off water to change a fridge filter? The water supply should always be turned off before changing a refrigerator water filter. This makes it easier to remove the filter and prevents water leaking into your fridge and onto your kitchen floor.

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