Introduction: Automatic Pool Water Filler

Picture of Automatic Pool Water Filler

This device will automatically add water to your pool when it gets below a specified level. It does this all for under $15. By having a device fill the pool to a specific level, you can avoid wasting water by overfilling.

Step 1: UPDATE: VERSION 2.1 Cross Section Added for Stability

Picture of UPDATE: VERSION 2.1 Cross Section Added for Stability

After version 1.0 kept falling over in the water, I added a cross section for stability. I spray painted the PVC Black to help protect it from the sun. It also makes it look much more finished.

Step 2: Materials

Picture of Materials

You Will need
(1) Toilet Tank Fill Valve
(1) 3/4" PVC Pipe (At least 2 feet)
(3) 3/4" PVC 90 degree Elbows
(1) 3/4" slip fit to 1/2" threaded reducer
(1) 1/2" threaded coupler
(1) hose threaded to 1/2" reducer (I would recommend using a brass fitting, as it is much more durable. The rotating part tends to pop off of the PVC ones.)
(1) AquaMend Underwater Repair Epoxy Stick
(1) Teflon Tape
(1) PVC Pipe Cement
(1) 3/4" PVC 4 Way Cross Section***
(2) 3/4" PVC End Cap***
PVC Pipe cutter (or saw)
Groove lock pliers

***Please see UPDATED section for picture of 4 way pipe fitting and end caps

Step 3: Cut the Vertical Piece

Picture of Cut the Vertical Piece

Cut the vertical piece of pipe that will hold the entire assembly low over the side of your pool.

Step 4: Add Elbows to Vertical Piece

Picture of Add Elbows to Vertical Piece

Add two of the 90 degree elbows to the vertical piece, facing opposite directions.

Step 5: Epoxy Toilet Valve Into 90 Degree Elbow

Picture of Epoxy Toilet Valve Into 90 Degree Elbow

Take the AquaMend epoxy out of its tube and cut off approx. 1 inch. Knead it together until a uniform color is achieved. Mold it into a string, and tear it in half. Set one part aside, and roll the other out, using the tube as a rolling pin. Get it long enough to wrap all the way around the threads on the valve. Wrap it on the threads and insert it into the tube as far as it will go. Use the second part you set aside earlier to form a nice, graduated seal on the pipe. Smooth this out with your fingers. Allow to harden for 1 hour before continuing.

Step 6: Cut 2 Shorter Lengths of PVC Pipe

Picture of Cut 2 Shorter Lengths of PVC Pipe

Cut two lengths of pipe around 6 inches each. Insert one into each of the 90 degree elbows on the vertical (long) piece.

Step 7: Assemble the Coupler

Picture of Assemble the Coupler

Take the the 3/4" Slip Fit to 1/2" Threaded Reducer. Wrap the threads in teflon tape, making sure to wrap the tape in the same direction you will be twisting the piece into the coupler. Repeat for the hose threaded to 1/2" threaded reducer.

Step 8: Attach Hose Coupler Assembly

Picture of Attach Hose Coupler Assembly

Attach the Hose coupler assembly to one of the short pieces of pipe on the Vertical pipe.

Step 9: Attach Toilet Valve to Vertical Assembly

Picture of Attach Toilet Valve to Vertical Assembly

Attach the toilet valve to the short pipe on the Vertical assembly

Step 10: Test Fit in Pool

Picture of Test Fit in Pool

Place the whole unit in your pool, and check to see if it sits around the right height. Connect it to your hose, but DO NOT turn the water on or it may come appart because the PVC has not been cemented yet. The valve is adjustable, as well as where the float sits, so make sure the float sits about midway in the water.

Step 11: Cement the PVC Together

Picture of Cement the PVC Together

If the test fit is the right size, go ahead. If it is not, either cut the vertical piece shorter, or cut a new longer one. Cover your work surface with towels or newspaper to prevent getting cement on it. Remove the joints one at a time and apply glue to the end in a circular motion. While inserting the pipe into the fitting, twist the pipe a 1/4 turn. Hold 30 seconds and wipe off excess cement. Repeat for remaining joints. Allow to dry for 2 hours before continuing.

Step 12: Test and Adjust in Pool

Picture of Test and Adjust in Pool

Take it out and place it in your pool. Connect the hose and turn the water on. Adjust the height of the valve and location of the float until the water shuts off.


bigmikelv (author)2014-06-19

i took a different approach. Its for my pond.

whosdadog (author)bigmikelv2014-06-19

What kind of valve did you use? It looks like the water is going in through the top.

bigmikelv (author)whosdadog2014-06-19

bigmikelv (author)whosdadog2014-06-19

Im not sure of the name. My mom had a $100 pool filler contraption that broke. I dissected it and found that in it. I then Shattered it on the ground. I went to the local pool supply store and they actually had a replacement one. It works awesome but cost me $25. i was leaving on vacation that day and I needed to get it working ASAP or I would have gone to Home depot and just made one from a toilet float. water is going in through the top and the white cone helps keep the water from spraying out.

diggler86 (author)2014-01-01

Just want to say thanks for the idea and share my video of mine

jzimmer (author)2011-03-14

Awsome just made mine

whosdadog (author)jzimmer2011-03-14

What kind of epoxy did you use?

shootr made it! (author)2016-01-10

I knew somebody had to have done this - great information and thanks to the other's who added lot's of helpful information. Still needs a little paint to pretty it up, then into the pool!

steven.davis.w (author)2013-07-17

Do you need to cover the hose? So the sun/heat and pressure does not make it spring a leak.

pcooper2 (author)steven.davis.w2016-01-06

Use a high-quality industrial hose that is in good condition and make sure the water pressure is 60 psi, or less, and it should be fine during a summer absence of a month or two.

davjon made it! (author)2015-06-07

Thank you very much for the detailed instructions. Mine's built and in use. Pool sits out in the sun all day and I'm constantly paying the evaporation god's, this makes payment a little simpler ;)

Punta Gorda Tom made it! (author)2014-08-30

I just made this, and I believe I made a significant improvement to the design. I used a Korky toilet valve with an internal float. Where in the current design the valve is epoxied into the 90 degree elbow, I substituted a "tee" for the elbow. On the bottom of the tee I glued a 3/4 to 1/2 threaded reducing adapter. I put a cap on the upright coming out of the top of the tee, and clamped the toilet valve to it using automotive type stainless steel ring clamps. I used a braided stainless steel toilet supply line to connect from the 1/2 threaded adapter to the toilet valve. This eliminates the need to epoxy the valve in (I had trouble with this on my 1st attempt). I used a braided stainless steel washing machine hose to connect to my outdoor faucet. I appreciate the ingenuity of the original post and was pleased to fabricate this for use when we are away from home for extended periods.

HogHunter (author)2013-06-21

I've been an Instructables fan for many years but I must say this is perhaps the best instructable I have seen. It is very economical, it includes lots of suggestions and it has upgrades. To top it all off, it will make me look like a superhero to my wife who maintains our pool and has left the water running too many times to count. We've had our pool for 22 years and I have never seen a solution so easy and efficient. While economy isn’t super important, I am unwilling to spend $30+ for the Hudson value as nice as it looks. I do believe I will build a bracket or some kind of method to secure the device to the wall of the pool. This isn’t so much for allowing it to be in while the l kids are in but to make sure it is properly mounted. I do agree with the post about using a hose intended to contain constant pressure, if and only if you intend to leave it in the pool all the time. As I do not intend to use it that way, I will not initially worry about that. We have several storage boxes around the pool and it would fit nicely in one of them while not in use.

Thanks so much for a great idea! If there was a way to nominate this for an award I would gladly do so.

hakk3r (author)2013-04-14

My pool already has this built in by the skimmer, don't most pools have this already too?

d00mz (author)hakk3r2013-06-19

Some do, some do not. for those that do not, it is very costly to add one after the fact.

d00mz (author)2013-06-19

This is awesome, just built mine as well. Testing it in the pool after it has dried overnight.

bg_askins (author)2012-07-19

fantastic! i'm going to use this with a rain barrel to keep my koi pond's water level up.

jsbfla (author)2012-05-21

Just finished mine - works slick. My Fluidmaster float was a loose fit in a 3/4" thread-slip adapter, so I just mixed up some JB Weld, coated the inside threads with it, and it tightened up perfectly. Thanks.

jzimmer (author)2011-03-14

no epoxy the float i got threads fit nice to a 3/4 coupler and as you can see i its an inturnal float so i was able to put it up against the poolside for less chanses to get broke

whosdadog (author)jzimmer2011-03-14

I have searched for hours trying to find that coupler. Is the float 3/4 or 7/8 thread? I have only ever seen 7/8 thread valves, and have never seen 7/8 couplers. Where did you buy it?

jzimmer (author)whosdadog2011-03-14

i got it from lowes not sure on the threads its made by korky . i just played around in the pvc area putting the whole thing together took it on pvc glued it and pressure tested it and vac tested and was hour long no air leaks

whosdadog (author)jzimmer2011-03-14

Ok thanks, I'll have to check Lowes. Do you know what the coupler was called?

flyznest (author)whosdadog2012-01-28

ballcock is the name assigned to the toilet valve thread.... i found a ballcock x 1/2 reducing adapter at my local ace... fits perfect on the toilet valve... for some weird reason it threads perfect to a 1/2" threaded pvc coupler, but not to any other fitting. i had half the staff at ace stumped on that one. but it works!!! thanx for the design! its brilliant!

whosdadog (author)flyznest2012-01-28


jongscx (author)2011-06-04

Oh my god... this is amazing.

How long does this take to fill a pool? I'm assuming the flow rate is much less than just an open hose.

whosdadog (author)jongscx2011-06-04

It would take days to fill a pool with it, if not a week. Sometime we forget to turn ours on after we shut t off to swim, and after a few days the water level will drop by 5 or so inches. It takes maybe 5 or 6 hours to refill that 5 inches or so. It is by no means fast. But it does it's job.

Freyberger (author)2011-05-05

Great idea. I have made one for an above ground pool and it works like a charm!!

hdhilli (author)2011-03-24

I just finished my version which works just great. I used a slip/threaded PVC fitting between the elbow and toilet fixture. This saved me because I used too much epoxy and has to drill out the opening. Replacement of the fixture will also be easier...just epoxy a new one on a new fitting and screw it into the existing assembly.

Zipdaddy (author)2011-03-16

Wow...This falls under the "Why didn't I think of that?" category for a lot of us!! I'll be making one for sure. FYI HINT....Use electrical PVC....It's UV resistant.

incognito53 (author)2010-08-15

I've thought about doing something similar to this for a while.. How bad of an idea would it be to tap the suction pipe going into the pump and connect thru a valve to the water supply? Reason why is, I really don't want any extra pipes going to the side of the pool

scubaru (author)2010-08-07

I am truly surprised this hasn't been thought of till now, I mean if something as simple as a toilet has an auto fill, why can't your personal pool have one? Haha...Great instructable man!

Mudbud (author)2010-07-26

what if people were splashing and jumping into the pool? it would make the water level unstable therefore turning the thing on and off for filling. Im not trying to be rude im just thinking about it before I make one.

whosdadog (author)Mudbud2010-07-26

I take mine out and turn it upside down. The gavity keeps it off. Or you could, you know turn the water off.

KJenkinsAF (author)2010-07-22

Dude, I'm rushing out to the plumbing store to do this RIGHT NOW...GREAT idea.

My name is not Steve (author)2010-07-08

I think the answer is a different float valve. I just found this online today. It should make the entire assembly much smaller too.

That's a great valve, and I think it would work perfectly. However, it also costs 2x as much as the entire assembly as of now. It would definitely make it a lot simpler, but would raise the cost to about $35+shipping (for the valve). The benefit of purchasing all of the parts at HD is that there is no shipping. Thanks though, and I'll definitely look into similar valves. It sure is more elegant, and I think that it warrants greater research. Great find!

I found a good price. $23 for high temp. plus $5 shipping.

Yeah, I'm not sure if I would need high temp. I think that may be temperature of the liquid, but it could be environmental too i suppose.

My name is not Steve (author)2010-07-05

Hello gents. This is similar to the idea I've been planning. My idea is essentially the same but offers the toilet filler protection. Encase the unit in a pvc pipe wide enough to contain the toilet filler. Use an end cap and drill a hole in the cap for the filler. Mount the filler just as you would in a toilet tank. Drill another hole or two in the cap (pipe too?) so water can get in. In my pool there is a small diameter pvc pipe near the surface and connected underground to to a house spigot. I'll get the appropriate connectors for that and figure out another way to to secure the unit. I'll probably just use an elbow on top and another length of wide pvc filled with a bag of rocks much like the store bought units. I'll put "feet" on it to keep it from rolling.

Yeah, I've thought about enclosing it before, but I don't see any real benefit to it. I've had the original outside for over a year and it has no problems. I am trying to figure out a better way to mount it though, that would allow me to use a braided hose rather than epoxy.

Regarding your need for a mount without epoxy, how about a second hose coupler for a 3/4 inch hose. Use as short a piece of hose as you need to fit it over the threads of the filler (not positive it will fit) and hose clamp it. The short piece should be rigid enough so the filler will still stand upright. I found a store in NV that makes custom hoses. The plumbing supply store just told me about them. Alas, there are no 7/8 brass fittings anywhere. :(

I see what you are saying, and that may work. I'm not sure about the 3/4 fitting the 7/8, but I suppose having it tighter would make it more watertight.

I just read that copper pipe is not good in swimming pools, but how about this? Use a short piece of copper pipe and appropriate fitting for the filler and a copper to pvc coupler on the other end. Could this assembly be painted or coated with something to protect it from the pool water? Just brain storming here. :-) I don't know if there's a copper fitting for the filler base.

Yeah, I think there is, but using copper would raise the price of the filler considerably. When I switched from a PVC hose fitting to a copper one, (PVC one kept popping off) it added $5 to the price. And that was just one piece. As for why it's not good in pools, I have no idea why.

freakyqwerty (author)2010-07-06

Doesn't a toilet have the same sorta system?

dchall8 (author)2009-03-24

This is really a good idea. Why do you epoxy the valve on instead of threading it on?

If you do not have a PVC pipe cutter, GET ONE. It cuts through pipe like a hot knife through butter. You only have to use it once to realize a hacksaw is a dangerous waste of time.

whosdadog (author)dchall82009-03-24

You need to use epoxy because the threads on the valve are a proprietary size. I could not find any fittings that were the correct size for the valve, or even close. Since the nut for the threads is provided with the valve, the manufacturer has no reason to make it a standard size.

darthstupie (author)whosdadog2010-06-29

Why not use a supply line that is made to connect to these valves and the PVC pipe. It wouldn't be as ridged but another mount could be made to hold the valve. Just a thought.

whosdadog (author)darthstupie2010-06-29

If you can find a fitting like that, that is commercially available, you will be my hero.

darthstupie (author)whosdadog2010-06-30

You should be able to use a toilet supply line (they are flexible, not rigid like PVC) available at most any home improvement store. They usually have to connect to another valve to cut water off to the toilet in order to make repairs such as replacing the automatic valve used in your instruclable. As for a fitting only, I do not know. I will ask one of the guys that work in the plumbing dept of the store where I work. Great instructable by the way.

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