Introduction: LED Water Purifier

I was walking through my local camping supply store the other day when I came across this water purifier that cost $50 (I know outrageous) Being the DIYer I am I took a closer look at it to find that it was simply Some UV lights. Then it hit me, I can make this way cheaper. So I did.

HINT: start your soldering iron and hot glue gun now so they warm up

Step 1: What You Will Need

Here is a list of all the tools and parts you will need.


- some ultraviolet LEDs, I used 4

-A small switch

-One resistor for each LED, Mine were 330 ohm

-Black tape/ Electrical tape

-Some wire

-Small plastic or glass container, This should be watertight and clear

-A battery, Mine was a 7.2 volt RC car battery


-Solder Iron


-Wire cutters/ strippers

-Hot glue gun with hot glue


I had some stuff but I had to buy the LEDs ($2 Each) and the switch ($1 for a pack of 5)


This is from the label on the bag that the UV LEDs came in.

"This LED produces intense ultraviolet light. Exposure to UV radiation can be harmful. Protect your eyes and skin when operating. Never look directly at the LED. Buyer assumes all risks using this LED."

Just so you know and don't try and hold me responsible either.

Step 3: Soldering Part 1

Now that you have everything Get out the soldering Iron and solder each resistor to each anode of your LEDs (anodes are usually the longer terminals)

Then wrap them in electrical tape.

Step 4: Soldering Part 2

Now solder all your cathodes together (the shorter end)

And solder your anodes together on the other side of the resistor.

then solder a wire onto each and wrap in electrical tape.

Step 5: Solder on the Switch (part 3 of Soldering)

Now onto the anode wire solder a little switch on. and solder a little more wire onto the other end of the switch.

And just in case you haven't caught on wrap your connections in electrical tape

I used a momentary switch because UV lights are dangerous and I would not want it to accidentally turn on and stay on.

Step 6: Time for the Container!

Now take that small little clear container and put your LEDs in while leaving the switch on the outside.

To get good results bend the heads of your LEDs to make sure that they make an even spread of light.

because i do not have plans to fully submerge my container I just made the top of it water resistant by sealing it with tape and hot glue.

Step 7: Hook It Up to a Power Source

I tried using a smaller battery for this but none seemed to prove themselves worthy so I Ended up using a 7.2 volt Nickel Cadmium R/C car battery.

It was fairly easy to connect but I did not solder direct to the battery because I NEVER do that no matter how much wire is in between. its just dangerous.

Step 8: Operation

To use it simply expose by partially submerging the UV LEDs to your water for about 30 seconds and your water should be good and 99.99% bacteria free.

Thanks for reading.

EDIT: ok so it turns out that the LEDs I got are not quite powerful enough but this still gives you the basic concept. I would recomend that you get some 240nM UV LEDs they will raise the budget but it is worth it.

EDIT: (3/1/15) I made this several


ChristopherW222 made it!(author)2017-05-24

This is a clever project, but please know that the plastic housing you put the LEDs in is almost certainly not UVC transmissive. Just because it looks clear to your eyes does not mean it is UVC transmissive. You would have to shine through something like fused quartz glass in order for the concept to work!

eggomez made it!(author)2016-12-29

Where did you buy UVC LEDs?

miraclerandy made it!(author)2017-01-06

TanL8 made it!(author)2016-01-04

the led you bought is a little expensive.

I bought one type that use for sterilizer water only need $15.24

TanL8 made it!(author)2016-04-28

now have a alternatives for 254nm led, that is $275nm uvc

it's cheap and similar function as 254nm, mainly use for water purifier.

miraclerandy made it!(author)2016-10-03

It would be interesting to see the output of the mentioned UV-C LED lamps. TO-39 cans should have relativity low outputs (~1mW) compared to SMD devices. For instance, Nikkiso SMD devices are at 12mW and 265nm with a price of ~$60.

Another point that most confuse is the wavelength needed for disinfection. The reason 254nm is common for UV systems is due to the fact that low pressure mercury lamps produce UV light at 254nm. The ideal wavelength for bacteria, however, is between 260-270nm depending on the specific type of bug you're trying to kill. LEDs are awesome as you can select the specific wavelength you need for the bugs you're trying to kill. It's exciting to see this technology develop!

lanzer22 made it!(author)2016-10-24

I can only find a 2.5mW LED on Ebay for $40. If there's any online reseller for Nikkiso LED's for $60 please let me know where I can find it.

BTW TanL8 works for SFLEDS. :) Too bad they don't have a proper store front. But judging from how much people on Aliexpress are charging, it won't be much of a savings compared to Ebay.

AndreM71 made it!(author)2016-02-06

The only way this will work is by using ultraviolet LEDs in the C band in the range of 100–280 nm

miraclerandy made it!(author)2016-03-31

To get more into it - we would need to build a few more things. If you want the LEDs to last you'll need a proper reactor and heatsink to pull the heat away. UVC LEDs are pretty low in efficiency compared to visible LEDs and they get worse if you just use them as plug and play.

UV LEDs are too complex for plug-and-play use!

ShreyA2 made it!(author)2016-01-06

what frequency leds

ShreyA2 made it!(author)2016-01-06

what frequency leds

ShreyA2 made it!(author)2016-01-06

what frequency leds

jknotts1 made it!(author)2015-09-22

the type of ultraviolet light you must use is type C the shortwave UVC it is also referred to as microbicide UV the LEDs are about $20.00 US and tend to have a minimum order of at least 20 of them. With something that can have pretty serious consequences if the device doesn't have the appropriate test results to verify efficacy such as this it is best to make sure that the instructions include all of the data. Waterborne illnesses are pretty serious.

arunavnayak made it!(author)2015-05-24


DonnH1 made it!(author)2015-03-27

Great subject. I have a similar use - sterilizing air, killing mould spores in it . I recycled a power supply metal box, installed a special ballast and pair of sockets and a germicidal fluorescent bulb. I also added a six inch fan. All of this was to circulate the air in a trailer we went camping in. Mould builds up in it over the winter and makes a real mess. Dry-Zee-Air balls, light bulb, that sort of thing don't work very well. My little germicidal lamp in a box with a fan work marvellously. My wife noticed that there was grunge on the walls and everywhere in our little trailer and I noticed yesterday that there was no UV output coming from the lamp any more. I have ordered a replacement plus a spare. I have also scoped out the internet for UV leds in the 200 to 300 nm range and haven't found what I was hoping for as suitable replacements. You can buy whole spools of the white ones and stick them to your 4 foot T12 fluorescent tubes and do a conversion over from fluorescent to led lighting in the visible spectrum and that works slick. Nothing in the spectrum I was hoping for. Like many of you I will go back to Google and do a search for that sort of thing periodically. Meanwhile I will keep using the germicidal lights, they last me about 4 years working several months over fall, winter, spring. Then I crack the windows open for air circulation and turn off the UV lights. By the way my germicidal light tube is only about 10" long and takes care of the air in our trailer which is a little over 6 feet wide and about 12 feet long. You'd need more or longer ones for larger trailers.

jessicaf made it!(author)2015-01-20

unless your LEDS are at or below 260nm, this is all useless. The reason why i know they are not 260nm LEDS, is because there is way too much visible light in that jar, and 4 260nm LEDS would cost about 800 bucks with a lot of hard work searching the web for a good price.

ggooch made it!(author)2015-01-07

For all this trouble, why wouldn't a drop or two of chlorine bleach per gallon kill the bacteria, even heating the water produced to 180 degreesF. or so could clean it up.

hai.tay.351 made it!(author)2014-10-19

put your water bottle in the sun it will kill some bacteria

tommywaynesmith made it!(author)2014-10-15

Wrong uv spectrum

haeshproject made it!(author)2014-02-26

There are no UV leds in the right spectrum with enough power for the right price. Wait 10 years and check back.

Blackice504 made it!(author)2014-03-04

Please i do not want to be rude or anything, but you could not be more wrong, the wavelength for 254nm +-10% are around and many people have posted sites that sell them on this page one post was 2 years ago, sure if your looking for these UV-C LED's on eBay they are few and far between on eBay and some of the Cree range provide very high powered LED's that are classed as Daylight.

So in short they are out there just few and far between and there are high power LED's out there.

I think the correct thing to say would be right now the LED's for UV-C filters have about the same power consumption as the Fluorescent counterparts to filter water in order for them to work as a UV filter, but the advantage of LED compared to UV fluorescent would be the lifespan and durability of the product.

Taking price into account, at a glance could look similar or more for LED UV-C but add to the fact you would be paying for a device the lasts longer and durable it should be cheaper in the long run, but running cost i do agree it's about the same for UV-C as the efficiency is not there yet in LED's for this spectrum.

haeshproject made it!(author)2014-03-04

As regards to spectrum i mean UVC. In regards to power i mean a 3 watt cree bulb. I buy high power leds and i have a cree UVC led 3 watt bulb and output is not even in the same order of magnitude as my florescent bulbs. Also even high power leds barely can penetrate water more than a few mm with led and maybe a few inchs with off the shelf flourcent. For industrial applications like waste water treatment there are ones that work for 3 foot ditches. An led bulb capeable of sterilizing water is not within the technical capabilities of mankind at this time,. If that was powerful enough to kill germs you would destroy that plastic bottle which is not uv resistant, hence why they use quartz in real sterilizers.

Blackice504 made it!(author)2014-03-04

did i say it was to be used for industrial applications: NO

Did i say that the efficiency is not there yet in LED for this Spectrum: yes

did i say that an LED of any wattage works at 3 foot: no

Have i used UV LEDS / UV lamps ect YES.

the fact is i did not indicate any of those values, you just assumed or added them in.

your words "As regards to spectrum i mean UVC." 100nm to 280nm

last time i checked 254nm is with in UVC sure its towards the UVB end of the scale but if you know anything about killing bacteria then you would know that 254nm is the wavelength does the damage.


Germicidal UV is delivered by a mercury-vapor lamp that emits UV at the germicidal wavelength. Mercury vapour emits at 254 nm. Many germicidal UV bulbs use special ballasts
to regulate electrical current flow to the bulbs, similar to those
needed for fluorescent lights. In some cases, UVGI electrodeless lamps
can be energised with microwaves, giving very long stable life and other
advantages[clarification needed]. This is known as 'Microwave UV.'

Lamps are either amalgam or medium pressure lamps. Each type has specific strengths and weaknesses

there are LEDS that have the wavelength of 254nm...............They are few and far between and you will not find them on stated.

I will not post a link to these LED's as others have already done that.

your words "In regards to power i mean a 3 watt cree bulb. I buy high power leds and
i have a cree UVC led 3 watt bulb and output is not even in the same
order of magnitude as my florescent bulbs."

i see where your getting this idea from your thinking about normal LED lights in your home are rated at 5watts and there = 50 watts personally there more like 60 watts with good ones, but as i Stated, UV LEDS are not efficient as there other counter parts, but they do have the advantage of been solid state and durability, last thing bud this is just a note for you in future the term bulb should not be used for LED as LED stands for Light Emitting Diode, the only relation to a bulb they have is they emit light.

so to respond to your question in order to get the same power based on the current technology you be very close to the same 1 per watt as stated.

Sorry if i was not clear enough on that if you like i can get you the exact figures but i am very busy today.

Last LEDS are already in many certified filters.

PS i have access to a microscope if you would like to see the results of LED UV light to bacteria i am more then happy to send a video.

haeshproject made it!(author)2014-03-05

LEDS definitely stand a chance to disrupt the market soon. There are LED disinfection units, and they either dont work well with any water fouling (such as tannins) or they are insanely expensive, but most likely both. For space application they are ideal which is why I was using them. However we resorted to mercury based due to crap performance and cost. I think its very important point you made that even though my LED supplier says it rated at 3 watts that really only 2.8 watt draw and the the UVC bulbs are only a few percent efficient as opposed to orange/red which has a much higher lumens per watt. Usually only 10s of mW of UV from 3 watt input.

Heres a LED purifier source.

nanoBorg88 made it!(author)2014-03-05

Thanks for making this instructable and starting this discussion.
A good method in checking if your producing the right wavelength of light; using the photoelectric effect!
I have access to a gold leaf electroscope and a piece of zinc metal. The near uv spectrum will do nothing to zinc, but anything with a wavelength shorter than about 350 (half way through uva band) will cause electrons to emitted from its surface. On a charged electroscope the leaves will drop as it is discharged.
If you wanted to be surer that you were in the uvc range you will need to use a different metal. Choose one from the list that has an threshold greater than 4.43ev
Looking through the list the more common ones would be aluminium or tin

Btw thought it might be a good idea to remind people that there's very little to none uvc in sunlight because it's absorbed in the atmosphere.

Hope this helps someone!

Blackice504 made it!(author)2014-03-04

Hi, mate i have spent too much time researching this subject as i want to make a UV Filter to be inline after my Eheim 2226 filter.

Some things i have mentioned in a reply on your page about using UV-C LEDS and i will try not to repeat my self here.

So about your project UV-Filters do work so you are on the right train of thinking how ever with out a pre-filter you device may not work as well as you think because all water has particle matter in it unless been filtered and distilled and even then some can be in the water and that's where UV Filters come in but only after the first process of water filtration has been done as UV is light and can only pass though some objects and even some objects that appear to be transparent may not allow some spectrum to pass through especially in the UV range even water will diffuse UV light and the deeper the body of water the more UV light defuses thus changing the wavelength of UV light making the filter less effective this is why need lots of power to overcome this, so that $50 dollar purifier may not be as outrages as you think, in fact most of the UV Filters i have looked at for my fish are around that price range for 36 watt of UV-C killing power ;) so then add on the cost of a batt and maybe a charger i would think it should cost more if it actually kills bacteria simply because its the same price as the ones that run on mains.

Also i really wound not 4 LED's would do the same job unless you leave it on over time and give it a shake every so often, so please health sake do not drink the water from that device unless you got it from a tap and have tested the time it takes to kill bacteria.

But great job on making your device and getting peoples minds thinking about the subject.

A fun thing you can do with UV with your device is to put old cooking oil and dish washing liquid in and having a really cool glow lamp.

moradofox made it!(author)2013-04-09

nrepak, are you sure you get UV-C LED (250-285nm) at $2 each? From your chamber, I see too much visible light. someone's comment is right, it looks UV-A LED(365-395nm), in this wavelength section, the germicidal efficiency is about 1/3,000 of UV-C.

LoganMackey made it!(author)2011-08-21

found manufacturer uv diodes with 240nM wavelength

lolzaniru made it!(author)2012-10-31

do u get it uv leds newhere in India?

LoganMackey made it!(author)2012-11-01

chamunks made it!(author)2011-11-21

You'd need to buy 1 million of these before they would be cheap enough to be worth it from these people.

TGGrimler made it!(author)2012-06-19

Ebay sells something called the P-light, which is supposed to disinfect your toilet at night. $8+/each plus crazy shipping from Australia.

On another note, there are multiple brands of water bottle caps that are meant to convert your water bottle into a camp lantern. They are solar powered and use LED bulbs. If you took them apart you could possibly install the appropriate uv LED bulb. If you replace only a few of the bulbs with UV and have a few with normal white LED and then use colored bottle to filter out the harmful light, then you should be able to have a water bottle, camp lantern, and water purifier in one. Unfortunately that increases cost.

brentonl made it!(author)2009-10-18

So, you claim that the water will be 99.99% bacteria free.  Have you tested that hypothesis with bacterial cultures?

SpiroExDeus made it!(author)2009-10-20

Surely the LEDs do not need to actually be IN the water. So long as the container doesn't filter UV light you could surely put the UV LEDs OUTSIDE the container.

Would be interesting to test this with proper cultures on petri dishes. Shame I don't have a lab / money / the scientific experience to do it...

Algag made it!(author)2011-06-06

*drum roll*

SpiroExDeus made it!(author)2012-01-16

:( May not have been the case when you posted that link but it's now showing as 'out of stock'

gcc_mtl made it!(author)2011-08-17

Your device does not kill bacteria:

1 - UVC is germicidal, thats between 100 and 280nM
2 - most plastics and glass filter out UV light

You need to use Clear poly-styrene plastic or cobalt glass for UVC to pass through, or stick the bulbs into the water without anything infront of them.

elting made it!(author)2011-07-02

i made one with a solar panel and baby food jar.i put it into my small platic pond and within 2 days the amount of green crap was cut in half.i wish i would of looked here first befor i went of the trouble of figureing it out myself.well thats the fun in it any way.nice diy

Strycn1n3 made it!(author)2011-03-07

it kills the bacteria sure but some water would still taste like S***

tweakinreaper made it!(author)2011-02-28

I think heat shrink tubing would be easier to put on. Dab each end of tubing with hot glue if worried about water penetration.

ego73 made it!(author)2011-01-17

If it does indeed nuke 99.99%, how awesome would it be to rig it for solar/rechargeable battery operation! Then rig it, all nice n compact, onto a cap for a 2 gallon plastic container. Cool!

safedrinkingwater made it!(author)2010-10-06

I can't find anything below 350nm! I've been looking at combining a UV-C water treatment (including sand filter) with DIY PV solar panels for a project in Cameroon (remote schools).
I understand UV-C LEDS will cost more but would like to get hold of some to develope the idea with a view that the price will come down eventually. Anyone know where i can get some?
I wouldn't have thought the 400nm LEDS used in this design actually have any effect? Maybe someone could test using a coliform presence test? fairly cheap to buy. I got some for £3.50 ($7?).

varun2021 made it!(author)2010-06-30

could you tell me how much current each of the uv led was consuming?

findoggydog made it!(author)2010-05-05

In some, if not all cases the UV light will be neutralised by the small container housing the light, therefore rendering it useless for the purpose outlined.

The danger of that is you will think your water is being purified, when it is actually no different than when you put it in the bottle.

But unless you have a bio-lab at hand there will be no way of knowing.

Personally I'm going to stick with the store-bought purifiers as they get thoroughly tested - I don't want gastro in the middle of no where.

n33r made it!(author)2009-10-11

cant u solder em in series connection it would much easier to handle

Pie+Ninja made it!(author)2010-04-18

You're silly.

Nyxius made it!(author)2009-07-12

Where did you get your UV diodes from?

nrepak made it!(author)2009-07-12

electric goldmine for the 400s look around for some 240nm ones they will set you back but work a lot better try an auction site to get them cheaper

Nyxius made it!(author)2010-01-24

Thanks man!

vatak made it!(author)2009-06-01

UV-c LEDs are the best for this application.

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