I'm searching for a dataset that correlates pH, TDS (total dissolved solids), salinity (in either PPM or percent), ORP (oxidation reduction potential), specific gravity and hardness with at least 500 samples to predict water hardness based on the other parameters using a random forest regression. It doesn't matter location or license as long as I don't have to pay. Timeframe is not important but recent data would be preferable. Ideally the dataset would be in CSV or Excel but JSON or web scraping is OK.
I've tried the USGS water quality portal but It doesn't seem to work