Make a Household Gravity Water Filter in 10 Mins

I wrote this instruct-able in an Australian accent. Sorry if it's a bit difficult to read as a result, but I cant speak american.

So. On to business. Our old water filter (mains connected) split open and started spraying water everywhere. The pressure was on to get a new one working asap (yes, that was a dad joke). I Looked at some options like Berkley, and decided I was too much of a cheapskate to pay that much. As a result, here is the design I came up with. Total cost $48 ($AUD) in parts (with one filter). 1 hr shopping and 10 mins to build it.

My wife's main design parameters were ... no plastic containers to reduce the plastic outgassing into the drinking water, and should remove chlorine taste, bacteria etc etc. Hence stainless steel everything (as much as possible).

My design parameters were ... if it's in the kitchen, I dont want it to look too ugly.

Re: stainless steel. You will note the plastic tap and cartridge. I plan to replace the plastic tap with a metal one. I cant do much about the plastic cartridge bits. They aren't the sort of thing you can make in the laundry. This falls into the "as much as possbile" clause.

Enjoy. or not ...

Step 1: Collect the Parts

Go shopping for parts.

a. 2 x stock pots (the cheaper the pot, the better). Stock pots tend to be taller than standard ones which are wider and fatter. 7.8 litre, $9.00 ea at BigW, These have glass lids, which means you can see when it needs refilling. If you want to supersize, get the 19 litre ones for $20 each and do the same thing.

b. Stefani plasitc Lift Tap at Bunnings Hardware. $12.90

c. Stefani Filter cartridge at Bunnings Hardware. $22.90

d. Stainless steel Dog bowl at cheapy junk shop (Bargain City) for $1. Really anything flat will do. It just has to lift the tap high enough to get a glass underneath it. I kinda like the look of the dog bowl though.

You can probably get bits cheaper on ebay, but I didnt want to wait 4 weeks for delivery.

Step 2: Collect the Tools.

You need to be able to drill reasonably clean (as in burr free) 12mm hole(s) and a 16mm hole in very thin material. Let me point out that drilling large diameter holes in thin material is best not done with a twist drill (ask me how I know this!). So I had (already) in my drill box, a tapered reamer, which is ideal. You can also use a hole-saw, but less people will have these, as they are more specialist. As the tapered reamer only went to 12mm, I also used a grinding stone to enlarge the hole. If you have the right size holesaw or a reamer that goes to 16mm, you wont need to do this.

a. Battery Drill

b. Tapered Reamer in 1mm steps

c. (optional) stone grinding bit.

Step 3: Drill a Hole for the Tap.

Make sure that the tap is high enough above the base of the pot to let the plastic nut fit on the inside. Mark it with an indelible marker and drill a pilot hole. Then drill out the 16mm dia hole here, but don't be in a rush with the reamer. Enlarge it with the round grinding stone if your tapered reamer isn't quite big enough. Don't use a large twist drill, as you will tear the metal and bork the whole thing.

Insert the tap with the supplied soft washers both inside and outside the pot wall. Place the dog bowl upside down on the bench, and place the pot on top of it.

I just put a non-slip mat between them. You could double sided tape the dog bowl to the pot if it bothers you.

Step 4: The Filter Section

Take one of the pot lids and unscrew the knob (mine needed a philips head screwdriver, yours may vary), leaving a hole in the center. Place this upside down on the lower half pot. It should slope down to the hole in the middle.

Drill a 12mm hole in the base of the pot. This is where it helps if you bought a really cheap and nasty pot. It wont have a thick base, so you can easily cut the hole. You may need to enlarge this slightly. 12mm is a very neat fit.

For mine, I wanted the option of adding more cartridges (upto 3) in case the flow rate wasn't high enough, so I drilled the 12mm hole off center enough to fit three cartridges in. (see the photo). If you only want one, then drill it in the centre of the pot's base. Now the drilling is all done, you probably want to wash everything thoroughly before adding the ceramic filter cartridges.

Insert and tighten the filter cartridge plastic nut. Install the soft washers to seal it all up. Cut any protuding plastic thread off flush with the nut.

Some notes here on cartridges.

I bought some (more expensive) doulton cartridges to try. They are the rounded top ones shown in the picture. They are supposed to do a better job, and they probably do, but they also run about 3 times slower.

Place the filter section pot on top of the upside down pot lid from the previuos step, ie on top of the first pot.

Place the remaining lid on top of the whole thing.

Fill it with water, and run it though for a couple of hours as per the filter instructions. Throw out the first batch to ensure any cartridge sediment goes down the drain, and not your throat.

Et Viola, nice clean tasting water.

Disclaimer:

While I spend a lot of time at Bunnings Hardware, they don't give me any financial support ....
I try not to spend any time at BigW.