Since I live in deep rural Croatia surrounded with heavy agriculture, I often wonder abut my drinking water quality. Since a lot of pesticides and fertilizer are used we do have some issues with arsenic or nitrate pollution of water sources. Since water professional water testing is expensive and not the most accessible solution, I googled to see what can be done with hobby electronics and DIY approach.
I found open source water quality testing platform and open source enzymatic-photometric nitrate testing system.
Both machines were developed by By Michigan Tech's Open Sustainability Technology like many other useful open source scientific devices. Casing and structural parts are 3d printed.
Detailed guides, software and manuals can be found at: