What is in Joliet drinking water
Joliet draws from deep sandstone wells. Deep aquifer water in northern Illinois carries naturally occurring radium, and the city treats for it. Treatment is not the same as zero. The 2023 Joliet water report listed radium samples as high as 7.18 pCi/L. The federal limit is 5. The EPA says drinking radium above that level for years raises cancer risk.
The city also disinfects with chloramine, a chlorine and ammonia blend that stays in the water longer than plain chlorine. It is what you taste and smell at the tap.
How the RO system works
Water passes through a sediment pre-filter, a carbon block, then the RO membrane. The membrane lets water molecules through and rejects most dissolved contaminants, which go to the drain. Clean water is stored in a small pressurized tank under the sink and runs through a final carbon polish on its way to a dedicated faucet.
- Fits in a standard kitchen sink cabinet.
- Dedicated faucet, optional refrigerator and ice maker line.
- Annual filter change, membrane every few years.
Why RO belongs with a softener and carbon
RO membranes last longer on softened water because scale is what kills them. The whole-home carbon tank pulls chloramine before it reaches the RO, so the small under-sink filters are not doing heavy lifting. The three systems are designed to work in that order, which is why we install them together for $2,999.
Read about the softener side of the bundle or see the full Joliet water quality breakdown.
RO on private wells
On well water RO is even more important because nobody is treating the water before it reaches you. It handles nitrates and radium at the tap. Bacteria, heavy iron and sulfur need their own treatment ahead of the RO, which we quote after seeing your test results.