How to test for heavy metal in water? Is there a way to test if water has toxic heavy metals. Samples to both the water and people who drink it are available. Preferably, it should be done with at hold materials. I could also borrow materials from a high school chemistry lab potentially.

I have already tried boiling, but that just showed that it is hard water, which luckily isn't dangerous. Any ideas?
For qualitative tests to work properly, you need a concentration sufficiently high to observe the effects, e.i. precipitation of heavy metal salts and/or color changes of solution. If heavy metals are present, they are likely to be in small concentrations (depending on how your water is filtered before it reaches your house).

If you are concerned about your water quality and want to check if heavy elements are present, you should contact a trustworthy laboratory that routinely analyzes water samples. They are likely to use trace-element techniques such as inductively coupled plasma mass spectrometry (ICP-MS) and ICP optical emission spectroscopy (ICP-OES), or maybe atomic absorption (AAS) techniques. This way you get accurate and precise quantitative measurements of almost all elements in the periodic table.