How to build a gravity fed water filter for under $60

This is by far the easiest and least expensive way to filter water on a large(ish) scale for household use. We use it to filter the water from our creek (which we is rumored to have giardia) for drinking water. There is a commercial version of this water filter that looks really slick (almost like a stainless steel coffee urn) but at $200 plus the cost of filters, it was out of our budget. So here is how to make one yourself for far less money.

You will need:

  • Three (3) five gallon food grade buckets with lids
  • A ceramic water filter kit. I got mine here but you can also get one on Amazon here. Your kit should include: a spigot, two 3/4″ rubber washers, one 3/4″ plastic nut, a ceramic fine water filter, two 5/8″ rubber washers, one 5/8″ wing nut, and a pre-filter sock.
  • A tape measure and sharpie
  • A drill and 3/4″ & 5/8″ & 1/16″ drill bits

Let’s get started!

The kit that I ordered came with excellent instructions but in case yours doesn’t, here is the procedure that we used:

  1. Drill a 3/4″ hole centered 2″ above the bottom rim of one of the buckets. 
  2. Screw the spigot into the newly drilled hole with a rubber washer on either side of the hole. When you can’t screw it in any further, straighten the spigot and place the plastic nut on threads. Tighten the nut to finger tight.
  3. Next, bust out your 5/8″ drill bit. Drill one hole through the center of one of the lids. Grab another bucket (not the one with the spigot!) and drill another 5/8″ hole through the center of the bottom of it. This will be where you install the ceramic filter. 
  4. Place the top of the lid against the bottom of the bucket and allign the holes. Put the filter element (shown here with the pre filter sock on it) inside the bucket and carefully put the treads through both holes, with a rubber washer on either side of the holes. Place the wing nut on the treads and tighten as much as you possibly can. You may need an extra set of hands for this process- there are a lot of moving parts and you need to be careful not to drop the filter.
  5. Now put the lid with the bottom of the filter poking through it on top of the spigot bucket. So now you basically have two buckets attached on top of each other separated by a lid. The filter is in the the top bucket (this is where you will be putting the “dirty” water) and the clean water will filter down into the spigot bucket.  Starting to make sense?
  6. Next, you will need to drill some small holes in the top rim of both buckets to equalize the pressure as water is moving from the top​ to the bottom bucket. We use a 1/16″ bit and drilled 4 holes in the rim of each bucket but you could use any small bit. Make sure to remove the plastic shards from the buckets after the holes are drilled.
  7. Now all that’s left is to test your handiwork! Use the 3rd bucket to haul water from the “dirty” source (pro tip: once your haul bucket is full of water, put a lid on it. This will prevent it from sloshing everywhere and will also prevent leaves and debris from falling in if you have to haul it back through the woods like we do.) Anyways, get your water and head over to your filter. Make sure that the pre filter sock is over the filter (this is actually really important- the sock filters out large particles like dirt and organic matter so that they don’t clog the ceramic filter). Pour some water into the top bucket. The sock might try and float up because of the air trapped underneath it- just squeeze out the air and push it back down. Fill the top bucket about half full and watch for any leaks. If you do have a leak, tighten everything up.
    Not a bad place to haul water from!

  8. Put a lid on the top bucket and you’re done! Easy, right?

Here are a few things to note:

  • The ceramic element will last for about a year (depending on use and amount of particulate matter in the water) so I wrote the date of installation in sharpie on one of the buckets to remind myself to replace it in one year if I have not done so already. A replacement ceramic filter element will run you about $20 and you can likely get it from the same place where you got your initial kit.
  • The rate of filtration is actually pretty slow on this (less than 1 gal/hr) so a little bit of forethought and planning is required to make sure that you always have water.
  • The pre filter sock needs needs to be cleaned and/or replaced when it gets really dirty
  • The ceramic filter element is super awesome and will filter out protists (yes, that includes giardia) and bacteria, as well as heavy metals, herbicides, and a whole host of other things (listed here)
  • Be cognizant of the fact that the filter cannot tolerate below-freezing temperatures, as freezing when wet could lead to cracking of the element, rendering the filter useless.
  • The water tastes delicious!
Advertisements

3 thoughts on “How to build a gravity fed water filter for under $60

  1. Where do you keep you water filter during winter months? As I am sure your temperatures drop way below freezing?

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s