Whole-house water filtration for Los Angeles homes

The right filter depends on what's in your water, so we start there. LADWP and other water departments publish an annual water quality report, and we test at your tap for hardness, chlorine level, pH and visible sediment. If you have a specific concern like lead from old fittings, we recommend a lab test so you have real numbers.

That matters because some suppliers disinfect with chloramine rather than free chlorine. Chloramine is harder to remove and needs a catalytic carbon media and more contact time. A standard carbon cartridge sized for chlorine won't do much against it.

A sediment prefilter catches sand, rust and pipe scale and protects the carbon stage behind it. Carbon reduces chlorine, chloramine, many taste and odor compounds and some organic chemicals. Together they cover the most common complaints in LA homes. Stacking the stages in that order also keeps the carbon from clogging early, which stretches the time between cartridge changes and keeps flow steady at the far bathrooms.

Carbon doesn't remove hardness. If scale is the problem, you want a softener on the main line alongside the filter, with the carbon stage first so chlorine doesn't wear down the resin. Carbon also doesn't remove dissolved salts or most minerals; for drinking water that's very low in everything, an under-sink reverse osmosis unit is the better tool.

• Sediment prefilter for sand, rust and scale
• Catalytic carbon for chloramine
• Standard carbon for chlorine taste and odor
• Under-sink reverse osmosis for drinking water
• Softener added separately when hardness is the issue

Cartridge systems use large housings with replaceable filters. They're compact, cost less up front and fit in a garage or along an exterior wall. The tradeoff is changing cartridges on a schedule, often every few months for sediment and longer for carbon.

Tank systems hold a bed of carbon that backwashes on its own, rinsing trapped particles to a drain. They last years between media changes and handle higher flow, which suits big homes and properties with several bathrooms. They need a drain and power, much like a softener, and more floor space.

Either way, we add a bypass and shutoffs so cartridges or media can be serviced without cutting water to the house for long.

In houses still on galvanized supply lines, rust and scale break loose inside the house, downstream of a filter at the main. A whole-house filter helps with sediment from the street, but it can't stop rust forming in the pipes behind your walls. If you see brown water mostly on hot lines or after the water sits overnight, the pipes are the source.

That's when a copper or PEX repipe does more than any filter. Our article on patching versus repiping galvanized lines covers how to decide. Many owners install filtration during the repipe, since the main is already open. Doing both in one visit means one water shutoff, one set of new fittings at the main, and a filter that starts life on clean pipe instead of catching years of loose scale.