Reverse osmosis is the gold-standard solution for drinking and cooking water in homes where the tap water has lead, chlorine, dissolved metals, or just an off taste you cannot put your finger on. The system mounts under your kitchen sink, pushes your water through a semipermeable membrane, and leaves behind the contaminants. What comes out the dedicated faucet is essentially pure water.

What reverse osmosis removes

The membrane is rated to remove particles down to a fraction of a micron. In typical Pittsburgh water, that means a standard RO unit reduces or eliminates:

• Lead (critical for older Pittsburgh homes with lead service lines or pre-1986 plumbing)
• Chlorine and chloramines
• Heavy metals (copper, mercury, arsenic)
• Dissolved salts and minerals
• Sediment and rust
• Bacteria, cysts, and many viruses
• Pesticide and herbicide residues
• VOCs and many pharmaceutical traces

What is left at the faucet is clean, pure water that tastes the way water is supposed to taste.

Standard RO vs. Halo RO Plus

We carry two reverse osmosis systems. This page covers the standard RO. For the upgrade, see Halo RO Plus.

The standard RO is the right call when you want excellent drinking water and the budget-conscious option. The Halo RO Plus is the right call when you want the smart faucet, the alkalinity boost, and the leak detector.

When you need reverse osmosis

The “If this, then that” chart routes the following symptoms to RO (standard or Halo RO Plus):

• Lead in water lines (the primary use case in older Pittsburgh neighborhoods)
• Chlorine and chloramines in drinking water
• Unpleasant smell or taste at the tap
• Issues with drinking water (anything off, anything you can taste, anything that does not taste like water)
• Metallic taste

Full map: If this, then that guide.

How RO works, in plain English

Tap water enters the system and hits a sediment pre-filter that catches the obvious stuff (rust flakes, particulates). Then it passes through a carbon pre-filter that removes chlorine, which would damage the membrane. The pre-filtered water then gets pushed against the semipermeable membrane under your home’s water pressure. Pure water molecules slip through. Dissolved salts, minerals, and contaminants get rejected and flushed down the drain.

The clean water collects in a small tank under your sink (about the size of a large coffee thermos). When you turn on the dedicated faucet at the sink, water flows from the tank, through a final polishing filter, and out the faucet.

The membrane is the heart of the system. It typically lasts 3 to 5 years in Pittsburgh water. The pre-filters and post-filters get swapped annually.

Installation

A standard RO install takes about two hours. The Wahl plumber:

1. Mounts the manifold and pre-filters under the sink (compact, fits in most cabinet bases)
2. Mounts the storage tank under the sink or in an adjacent cabinet
3. Drills a hole in the counter or sink deck and installs the dedicated faucet
4. Taps into your cold water line for the RO feed
5. Connects to your drain line for the reject water
6. Connects to your refrigerator water line if you want filtered water to the fridge and ice maker (optional)
7. Runs the system through its initial flush cycle

The unit needs no electricity. It runs on the existing water pressure in your home. If your incoming pressure is below 40 PSI we will recommend a booster pump. See Grundfos SCALA2 Booster Pump.

Maintenance

• Pre-filters and post-filter: replaced once a year
• Membrane: replaced every 3 to 5 years
• Sanitize: every 1 to 2 years

Wahl Club members get filter changes scheduled with their annual maintenance visit, no separate trip required.

RO vs. the alternatives

vs. Halo RO Plus. Halo RO Plus is the upgrade. Same membrane technology, plus alkalinity booster, smart faucet with filter alerts, and leak detector.

vs. Always Fresh. Always Fresh is a compact under-sink carbon filter. It reduces chlorine, lead, and some contaminants, but it does not have a membrane and does not match RO performance on dissolved solids and a broad contaminant list. Less expensive. Less thorough.

vs. Whole Home Carbon Filter. A whole-home carbon filter treats every tap in the house but at a lower removal grade than RO. The right pairing for many Pittsburgh homes: whole-home carbon for chlorine everywhere, RO at the kitchen sink for drinking water.