Is There Chloramine in San Diego County Tap Water? Why the Type of Carbon Filter Matters

Which San Diego County water utilities use chloramine?

Most of them, by their own reports. The City of San Diego, Helix, Escondido, Oceanside, Vista Irrigation District, Vallecitos, Rincon del Diablo, Ramona, Padre Dam and Sweetwater all name chloramine. Carlsbad, Olivenhain and Otay list a total chlorine residual without naming the form. Poway named chloramine through CY2024 and changed its wording in CY2025.

The practical takeaway: if you are on city or district water almost anywhere in the county, assume chloramine until your utility tells you otherwise. It takes one phone call to confirm, and the number is on your water bill.

What is chloramine, and is it safe to drink?

Chloramine is chlorine combined with ammonia. The EPA says it provides longer-lasting disinfection as water moves through pipes, and that water containing chloramines that meets EPA standards is safe for drinking, cooking and bathing. The CDC says chlorine or chloramine levels up to 4 mg/L are considered safe in drinking water.

Utilities use it because it stays in the water longer than chlorine alone, which matters in a system with long pipelines, and because it forms fewer disinfection byproducts. Poway's reports described it that way for years: a combination of chlorine and ammonia that further improves the water supply and reduces the formation of disinfection byproducts.

The EPA and the CDC both describe chloramine as safe for drinking at regulated levels. The reports we reviewed show residuals around 2 mg/L on average, under the 4.0 mg/L regulatory maximum. There is no reason to be alarmed by chloramine in your water. There are good reasons to know it is there, which are below.

Who needs to remove chloramine?

Three groups. Anyone using home kidney dialysis, because the EPA says chloramine must be removed before water is used in dialysis machines. Anyone keeping fish, amphibians or reptiles in water, because chloramine harms them through their gills and skin. And anyone bothered by the taste or smell, which is a comfort issue, not a safety one.

The EPA's guidance on dialysis and aquariums is specific: chloramine must be removed before use in dialysis machines and neutralized for aquariums, and dialysis patients can safely drink chloraminated water. If you do home dialysis, follow your care team's instructions; do not rely on a household filter for that.

One old trick does not work here. The CDC notes that you can remove chlorine by letting water sit out for a few days, but you cannot remove chloramine that way. Aquarium owners need a water conditioner made for chloramine.

Why is chloramine harder to filter than chlorine?

Chloramine is a small, stable molecule, so it reacts with ordinary activated carbon much more slowly than chlorine does. A filter that strips chlorine taste in a fraction of a second of contact may let much of the chloramine through. Carbon made to be more reactive, called catalytic carbon, was developed to handle it.

The Water Quality Association, the water treatment industry's trade group, describes chloramines as small, stable molecules that are difficult to remove by distillation, reverse osmosis and ion exchange, and says traditional activated carbon can need a long contact time to break them down. It also says newer carbons with increased catalytic activity are especially effective at removing chloramines.

Contact time is the part people miss. Water has to spend enough time in the carbon for the reaction to finish. A small pitcher or faucet filter, or an undersized whole-house tank, may not give chloramine that time, which is why two filters that both say carbon on the label can perform very differently here.

What should you look for in a carbon filter for chloramine?

A certification, not a label. NSF/ANSI Standard 42 covers aesthetic claims, and chloramine reduction is one of the specific claims a product can be certified for under it. Look for that exact claim, not just chlorine reduction, and check it in NSF's public listings before you buy, whether it is a pitcher, an under-sink unit or a whole-house system.

NSF's standards page lists chloramine as a claim under NSF/ANSI 42, and NSF publishes a searchable list of products certified for chloramine reduction. Any installer should be able to tell you which carbon is in their system and whether it carries that claim. That includes us, so ask us the same question.

Reverse osmosis systems deserve a note. An under-sink RO unit is excellent at dissolved solids, but chloramine is one of the things it is not good at on its own. Good RO units put a carbon stage ahead of the membrane, and for chloramine that stage matters as much as the membrane does.

Does a water softener or salt-free conditioner remove chloramine?

No. A softener removes hardness minerals through ion exchange, and a salt-free conditioner changes how those minerals behave. Neither is designed to remove chloramine. If taste or smell is the complaint, the carbon stage is what does that work, which is why whole-home systems pair treatment for hardness with a carbon filter.

Our whole-home systems include a triple-purpose pre-filter with sediment, carbon and zinc stages ahead of the softener or conditioner. Our salt-free vs softener comparison covers what the main system does, and our cost post covers what each system includes and costs.

If taste at the kitchen tap is your only complaint, a whole-house system may be more than you need. A certified point-of-use filter at one tap is cheaper and addresses exactly that.