Coffee Maker: Auto-Fill Hack

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Coffee Maker: Auto-Fill Hack
Coffee auto-fill means never having to wait. Photo: Andrew Terranova
Coffee auto-fill means never having to wait.
Photos by Andrew Terranova.

Morning is challenging enough. The day is just starting, and I’m barely functional as I make my first cup of coffee. (Yeah, I’m and addict. So what?) The last thing I need is to hear that awful sucking sound that means the reservoir on my Rancilio coffee maker is out of water. I already had to wait like… two minutes for it to warm up. How am I expected to wait another minute while I refill it? The sink is all the way across the kitchen!

A time comes when you have to say, “I’m not going to take it anymore!” Well, I don’t have to worry about that since I discovered this pretty simple hack by Terry Stockdale to add a water line to the coffee maker. It only takes a few dollars in parts, and if your refrigerator already has a water line running to it, it’s easy to tap into that.

I’m not going to try to reproduce Terry’s blog. It’s already easy to follow. I will add a few comments.

    • First, if you are going to do this, I recommend adding a water filter, if you don’t already have one. Gunking up your nice coffee maker with hard water deposits or other stuff is a bad idea.
    • Second, you could easily adapt this hack to other brand coffee makers. Anything that uses a reservoir would probably work. You may need to hunt around for a float valve with the right dimensions.
    • Third, if it doesn’t seem to you like a big improvement to have water on demand for your coffee maker, maybe you should be drinking more coffee.
    • Fourth… er, there is no fourth thing. Take a look at the pictures below to get an idea of my setup.

18 thoughts on “Coffee Maker: Auto-Fill Hack

  1. SaluteCaffettiera: Auto-Fill Hack | Salute says:

    […] Aggiunta di una linea di acqua di riempimento automatico per la tua macchina per il caffè è piuttosto semplice, e consente di risparmiare tempo ogni giorno. […]

  2. 커피 메이커에 자동 급수 장치 설치하기 | Make: Korea says:
  3. unmaintained says:

    I did the same thing to my Silvia but found the float valve not 100% effective. I suggesting leaving a ball valve or cut off in the line as well, it makes it fool proof and still much easier than refilling manually. Just open the cut off valve every so often and the float will prevent you from overfilling, but turning the cut off back on when you’re done will prevent any float failure.

    1. Andrew Terranova says:

      I used the float valve recommended in the linked blog post from Terry, and it works perfectly fine. The float is adjustable and I was able to adjust it for reliable operation. The reservoir doesn’t fill all the way to the high water mark, but since it auto-fills as I use water this is never a problem. I have never had a single overflow issue since I adjusted the valve float.
      I do have a cut-off valve in line near the water filter, which is very handy when I’m doing maintenance.

  4. greg says:

    I have a regular coffee maker with a reservoir. I would like to do this, but I am confused about one detail. If the water is controlled by a float valve that’s good, it means that the reservoir won’t overflow. But it also means that as the coffee is produced, water is consumed, and the the float valve will let more water into the reservoir. So you end up making coffee constantly and I guess the carafe ends up overflowing. What I need is a way to fill the reservoir exactly once.

    1. toelius says:

      Greg – i have the same issue. I had a Brew Express for just over a year (of course, warranty ended at 12 mos.), and it crapped out me. I got spoiled by the auto-fill, and found this site as a hack — which i spent this morning attempting to execute on a new coffee machine from BBBeyond. Fortunately, I hadn’t drilled in to the water reservoir (was just about to … Got the float ready and had the water line ready). I tested the water depletion rate of the reservoir, and was about to test the fill rate of the water line so that I was certain the reservoir wouldn’t go dry during the brew process. Then I wondered … Does this thing stop when it is dry (runs out of water), or by some programming? It is the former – so, yeah … This won’t work with most brewers. I am searching for a solution … If anyone else out there has an idea, reply.

      1. Andrew Terranova says:

        Greg and Toelius are correct. This hack is not for a standard drip coffee maker. Those rely on a set amount of water put into the reservoir for each pot brewed.
        The only thing I can think would work for auto-filling that kind of pot would be something that could fill a measured amount of water. Even then, you lose the flexibility to say, make half a pot of coffee instead of a full pot. Unless you allow multiple settings for in your system for different water volumes. It starts sounding more complicated than practical.
        I’m sure there must be a way to do what you are looking for, but this is not it. Let us know if you do find a way, and we’ll publish it!

  5. Assistmymovement.Com says:


    Coffee Maker: Auto-Fill Hack | MAKE

  6. Ground Up: 7 Stimulating Coffee Hacks | Make: says:

    […] coffee machine makes that awful sucking noise when it runs out of water? We do too, which is why Andrew hacked his coffee machine to fill with water automatically. This project can be as simple as adding a water line, although a filter is also a good idea if you […]

  7. NehmoSergheyev says:

    Where did you get the float valve?

    1. Andrew Terranova says:

      If you follow the link to Terry’s original hack, you can find the model number (#23099), which is still available from

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Andrew Terranova is an electrical engineer, writer and author of How Things Are Made: From Automobiles to Zippers. Andrew is also an electronics and robotics enthusiast and has created and curated robotics exhibits for the Children's Museum of Somerset County, NJ and taught robotics classes for the Kaleidoscope Enrichment in Blairstown, NJ and for a public primary school. Andrew is always looking for ways to engage makers and educators.

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