I have had a <removed> meter for years, from Lazada. Our water is from a communal borehole, supposedly filtered before distribution, and reads 240+ out of the tap, and stings like hell if you get it in a cut!
The same water after passing through our reverse osmosis system reads between 4 and 16, depending on time since filter replacement, normally six months or so for carbon and particulate, and salt for the resin. The r-o filter lasts two years. The <removed> is highest immediately after filter change and reduces over time, then creeps up when changes are due. There is no residual taste to the water.
Bottled water bought outside generally reads 38 or more.
The chart on the stick says anything under 150 is safe to drink!