How to refill a "disposable" Brita brand water pitcher filter with activated carbon.

Step 3: Making the hole.

You will notice on the top of the Brita filter cartridge some radial slots for allowing water into the filter. The overall diameter of the slot pattern is just under 1/2". I've drawn a black line where you'll want to make your cuts. As the plastic is thin, be careful not to get too happy with the knife... stay calm. :)

Dump out the original contents. You will notice what look like little glass beads in with the charcoal... I believe these are resin beads and are primarily used to remove heavy metals. Have your water tested to see if you have heavy metals that you would want removed. If so, you'll likely want to go with a filtration system that includes these beads.

As a side-note, some of the PuR filters (owned by Proctor & Gamble) now (as of March, 2008) come with a timed release version of sodium fluoride, which is toxic to mammals. You can read up on the fluoride controversy here ( http://www.fluoridation.com/ ), or you can Google the terms fluoride + poison. (2013 Update: PuR no longer sells their filters that "adds benificial flouride to your water")

Once you've got the hole roughed out, you can smooth it round with your knife, or you can use a 1/2" drill bit to ream out the hole. If you use the bit, set the drill on the higher gear range, as the faster bit speed will make a smoother, rounder hole. While you want a fast bit RPM, you want to insert the bit into your rough hole slowly so that you don't end up with tears in the plastic. You can actually use the fast moving bit to melt the hole, which will preserve the integrity of the plastic. Reversing the drill will provide friction/heat & help prevent tearing the plastic.

Finish up this step by trimming any excess plastic from around the hole and dry-fitting your plugs. Adjust the hole diameter with your knife as necessary... this isn't rocket science, the hole simple has to be tight enough to retain the plug so that the rim/shoulder of the plugs sits parallel with the surface, as shown in the photo.

Comments

[Agnis]

No need to make the hole really really smooth and then punch holes in the top to ensure water flow into the canister. Make a hole, make sure what you are plugging it with won't come out, but a few little spaces at the edge really don't matter. As I said in the previous comment space, I use corks. Just make sure they are tightly in, so they don't float up and out.

[Bdixon]

Those 'bead' are NOT filler but ionic-exchange resin. See: http://en.wikipedia.org/wiki/Ion_exchange_resin
They help eliminate lead (copper) and some chlorine compounds. Therefore your instructible is NOT a 100% functional replacement for a Brita Filter. They are very expensive ($100 for 50g on ebay... so probably would add a $ or two to cost of refill).

[kcoldie]

I have the same concerns. Charcoal filters out organics leaving any chaged ions, e.g. metals, remaining in the water.

[kd1s]

And because of more stringent public water supply regulations, the Providence Water Supply where I live has been chlorinated for about 12 years now. It never used to be until the stricter testing and regulations went into effect.

[endolith]

Fluorides are different from fluorine, and the toxicity depends on what you compound it with. The fluorides used in water are compounds of fluorine and other elements, such as sodium hexafluorosilicate or hexafluorosilicic acid. The beneficial effect on teeth was discovered from natural mineral deposits dissolving into drinking water in Colorado.

[firelizzard]

Chlorine is poisonous and it is in our water. Unless the amounts of Fluorine used are significantly more poisonous than the amounts of Chlorine used, there is not much of a difference. In some places, Fluorine is used instead of Chlorine to sterilize tap water.