Whole home water filtration, Hidden Hills, CA.

Hidden Hills water hardness: 8 GPG, consistent year-round

The LVMWD 2024 Consumer Confidence Report documents hardness at 8 grains per gallon (148 ppm CaCO3 average) across the LVMWD service area, which includes Hidden Hills. This reading qualifies as moderately hard and is consistent with the Colorado River and State Water Project blend that MWD processes for LVMWD.

At 8 GPG, scale deposits form on water heater heating elements within the first year. Tankless water heaters are particularly vulnerable because scale builds up on the narrow heat exchange surfaces and reduces efficiency rapidly. High-efficiency dishwashers, steam ovens, and inline humidifiers all accumulate scale deposits at the same rate, reducing lifespan and requiring premature replacement. A kation-resin softener removes calcium and magnesium through ion exchange before water reaches any appliance, eliminating scale formation at the source.

On the disinfection side, MWD treats imported water with chloramine rather than free chlorine. Chloramine is a combination of chlorine and ammonia that remains stable over the long distribution distances involved in moving water from the Jensen plant to Hidden Hills. Unlike free chlorine, chloramine does not off-gas at the tap when you run the water. A whole home catalytic carbon filter provides the correct treatment by breaking down chloramine through a catalytic oxidation reaction rather than simple adsorption. Standard activated carbon filters are not effective against chloramine at whole-home flow rates.

Source: LVMWD 2024 Consumer Confidence Report (hardness data, disinfection methods)

Sizing for larger custom homes in Hidden Hills

Hidden Hills is a gated residential community of large custom homes, many with 3,000 to 7,000 square feet or more of living space and multiple bathrooms, dedicated laundry rooms, outdoor irrigation connections, and high-flow appliances including steam showers, tankless water heaters, and professional kitchen equipment.

Whole home filter systems are rated by flow rate in gallons per minute. A system sized for a standard 2,000-square-foot home will restrict flow in a 5,000-square-foot home during morning peak usage, when multiple showers, dishwashers, and appliances run simultaneously. Before recommending any system, we measure the actual flow rate at the main supply line and review the household fixture count. This determines the correct filter diameter, media volume, and softener grain capacity.

As a licensed general contractor, we also handle any associated work: cutting into the main supply line, installing the bypass valve, adding the appropriate drain connection for the softener, and finishing any wall or floor penetrations involved in routing the new supply lines. The whole installation from permit to final walkthrough is handled under one license and covered by the same 5-year parts and labor warranty.

Frequently asked questions

How hard is the water in Hidden Hills, CA?

Hidden Hills is served by Las Virgenes Municipal Water District. The LVMWD 2024 Consumer Confidence Report shows hardness at 8 grains per gallon (148 ppm CaCO3 average). The hardness is consistent year-round because LVMWD sources near-100% MWD imported water with no local groundwater dilution. At 8 GPG scale on water heater elements forms within the first year. Verify current readings at lvmwd.gov.

Does Hidden Hills use chloramine or chlorine in the water supply?

LVMWD water is treated with chloramine by Metropolitan Water District at the Jensen Water Treatment Plant before delivery to Hidden Hills. Chloramine is more stable in distribution than free chlorine but does not dissipate at the tap. A catalytic carbon whole home filter is required to address chloramine. Standard activated carbon does not break down chloramine at the rate needed for whole home treatment.

What whole home water filter is right for Hidden Hills homes?

For Hidden Hills homes on LVMWD supply, the correct approach is a whole home catalytic carbon filter for chloramine and disinfection byproducts, paired with a kation-resin softener for the 8 GPG hardness load. The two systems address different problems and install together at the main supply line in a single visit. For large custom homes we size each system to the actual flow rate at the meter rather than a default configuration.

Is Hidden Hills water quality consistent year-round?

Yes. Because LVMWD sources near-100% MWD imported water with no local groundwater supply of its own, Hidden Hills water hardness holds near 8 GPG year-round. This differs from LADWP zones where seasonal blend shifts change the hardness load. The consistent hardness profile strengthens the case for a permanent softener rather than a seasonal approach.

Do Hidden Hills homes need a whole home filter or just a drinking water filter?

Most Hidden Hills homeowners benefit from both. A whole home catalytic carbon filter addresses chloramine throughout the house, protecting appliances, water heaters, and fixtures. A softener addresses the 8 GPG hardness that causes scale damage to tankless water heaters, dishwashers, and steam systems common in larger custom homes. An under-sink reverse osmosis system at the kitchen tap provides highest-purity drinking water. The three systems address different problems and are typically installed together.

How do I get a water filtration estimate for my Hidden Hills home?

Contact Noohi Construction by phone or the contact form to schedule a free water test at your home. We test for hardness, chloramine presence, and total dissolved solids before recommending a system configuration. For larger custom homes we also assess peak flow rate at the main supply line to size the filter and softener correctly.