3 ms·

I live in Seattle, WA, which apparently has some of the cleanest water in the country. I use one of those under-the-sink inline charcoal cartridge filters on t

by billti 6y ago

I live in Seattle, WA, which apparently has some of the cleanest water in the country. I use one of those under-the-sink inline charcoal cartridge filters on the sink we use to make tea or cook with. If I grab some water from a different tap, you can tell immediately by the smell (chlorine) and the taste. I'm surprised the filter takes out the chlorine honestly, but it's clearly taking out a bunch of stuff from what is otherwise considered very clean. That said, having travelled extensively through places like India, South America, East Asia, etc., I'm certainly grateful for the water we have "on tap" in the house. It's easy to take for granted.

Gibbon1 6y ago
Small tidbit, ascorbic acid kills chlorine and chloroamine.
- loeg 6y ago
  You can also just let the water sit and the chlorine will evaporate out.
  - Gibbon1 6y ago
    True with Chlorine, chloroamine not as much.
    - loeg 6y ago
      Sure; I did not say otherwise. Seattle (where OP lives) does not use chloramine. > You might hear about different forms of chlorine. Seattle's water system uses "free chlorine" (not chloramines). http://www.seattle.gov/utilities/your-services/water/water-system/cedar-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s...
loeg 6y ago
You can blame the EPA for mandating chlorination in Seattle's water supply. The watersheds that feed into Seattle drinking water are "Surface Water" and considered high risk by the EPA. This risk assessment is probably more accurate in the rest of the country; our protected watersheds are fairly uncommon. But we don't get any special exemption. EPA mandates a floor of 0.2 mg/L chlorine for all Surface Water based drinking water supplies at all times[0]. There are additional chlorine requirements depending on what sort of filtration you perform, if any, and how far the first service connection is from the chlorine insertion, in minutes. (They also mandate a safety ceiling of 4 mg/L for all drinking water.) This level is continuously monitored. Seattle does about 1 mg/L to meet these EPA-imposed requirements.[1] Chlorine evaporates out of water, so if you don't like the taste, you can just let tap water sit a while. Sunlight helps. Boiling water (e.g., for tea) also removes most of the chlorine. [0]: (PDF) https://www.epa.gov/dwreginfo/swtr-plain-english-guide https://www.epa.gov/dwreginfo/swtr-plain-english-guide [1]: (PDF, p. 8) https://www.seattle.gov/Documents/Departments/SPU/Services/Water/Water_Quality_Report_2019.pdf https://www.seattle.gov/Documents/Departments/SPU/Services/W...
- namibj 6y ago
  Weird. Here in Germany we have some protected watershed areas on smaller rivers that directly feed a surface reservoir, created in the river valley through a dam. They get filtered, but there is no chlorine directly. Some chlorine dioxide is used at the end, though. Here's the official description of the utility, translated to english: - Via a raw water pumping station, the dam water first reaches the micro-screening plant. It removes coarse contaminants over 35 ~ µm in diameter through stainless steel mesh filters. This provides special safety in times of mass algae growth or during floods. - Subsequently, the raw water is de-stabilized with a flocculant; and turbid matter accumulates to form large flocs. - In filter stage 1, two filter materials of different coarseness are used to remove the flocs. - Ozone is then added to disinfect the raw water. - Filter stage 2 is equipped with activated carbon and frees the raw water from the reaction products of ozonation. Excess ozone reacts to form oxygen and is thus removed from the raw water. - The further filter stage 3 uses natural limestone material over which the water flows. Here the excess carbonic acid in the water is removed. Finally, a small protective disinfection with chlorine dioxide takes place before the drinking water leaves the clean water tank in the direction of <city>.
  - loeg 6y ago
    The steps are similar in Seattle, although I think we filter less. I'm having a hard time finding a concise but also technical description of water treatment steps. We definitely do: - Ozone disinfection, and removal - Tolt river supply only: water conditioning by filtering through "granular media." (Cedar river supply is clear enough without this step.) - UV disinfection - pH adjustment to avoid corroding pipes - Flouridation for public health - Chlorination as a final step as water leaves the treatment plant, and also at some downstream facilities (like a networking repeater; just to maintain chlorine levels that would otherwise have fallen due to distance from the upstream chlorination site) Tolt: http://www.seattle.gov/utilities/your-services/water/water-system/tolt-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s... Cedar: http://www.seattle.gov/utilities/your-services/water/water-system/cedar-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s...
TedDoesntTalk 6y ago
Is there a health risk to consuming chlorine in water?

by billti 6y ago

Gibbon1 6y ago

Small tidbit, ascorbic acid kills chlorine and chloroamine.

loeg 6y ago
You can also just let the water sit and the chlorine will evaporate out.
- Gibbon1 6y ago
  True with Chlorine, chloroamine not as much.
  - loeg 6y ago
    Sure; I did not say otherwise. Seattle (where OP lives) does not use chloramine. > You might hear about different forms of chlorine. Seattle's water system uses "free chlorine" (not chloramines). http://www.seattle.gov/utilities/your-services/water/water-system/cedar-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s...

loeg 6y ago

You can blame the EPA for mandating chlorination in Seattle's water supply. The watersheds that feed into Seattle drinking water are "Surface Water" and considered high risk by the EPA. This risk assessment is probably more accurate in the rest of the country; our protected watersheds are fairly uncommon. But we don't get any special exemption. EPA mandates a floor of 0.2 mg/L chlorine for all Surface Water based drinking water supplies at all times[0]. There are additional chlorine requirements depending on what sort of filtration you perform, if any, and how far the first service connection is from the chlorine insertion, in minutes. (They also mandate a safety ceiling of 4 mg/L for all drinking water.) This level is continuously monitored. Seattle does about 1 mg/L to meet these EPA-imposed requirements.[1] Chlorine evaporates out of water, so if you don't like the taste, you can just let tap water sit a while. Sunlight helps. Boiling water (e.g., for tea) also removes most of the chlorine. [0]: (PDF) https://www.epa.gov/dwreginfo/swtr-plain-english-guide https://www.epa.gov/dwreginfo/swtr-plain-english-guide [1]: (PDF, p. 8) https://www.seattle.gov/Documents/Departments/SPU/Services/Water/Water_Quality_Report_2019.pdf https://www.seattle.gov/Documents/Departments/SPU/Services/W...

namibj 6y ago
Weird. Here in Germany we have some protected watershed areas on smaller rivers that directly feed a surface reservoir, created in the river valley through a dam. They get filtered, but there is no chlorine directly. Some chlorine dioxide is used at the end, though. Here's the official description of the utility, translated to english: - Via a raw water pumping station, the dam water first reaches the micro-screening plant. It removes coarse contaminants over 35 ~ µm in diameter through stainless steel mesh filters. This provides special safety in times of mass algae growth or during floods. - Subsequently, the raw water is de-stabilized with a flocculant; and turbid matter accumulates to form large flocs. - In filter stage 1, two filter materials of different coarseness are used to remove the flocs. - Ozone is then added to disinfect the raw water. - Filter stage 2 is equipped with activated carbon and frees the raw water from the reaction products of ozonation. Excess ozone reacts to form oxygen and is thus removed from the raw water. - The further filter stage 3 uses natural limestone material over which the water flows. Here the excess carbonic acid in the water is removed. Finally, a small protective disinfection with chlorine dioxide takes place before the drinking water leaves the clean water tank in the direction of <city>.
- loeg 6y ago
  The steps are similar in Seattle, although I think we filter less. I'm having a hard time finding a concise but also technical description of water treatment steps. We definitely do: - Ozone disinfection, and removal - Tolt river supply only: water conditioning by filtering through "granular media." (Cedar river supply is clear enough without this step.) - UV disinfection - pH adjustment to avoid corroding pipes - Flouridation for public health - Chlorination as a final step as water leaves the treatment plant, and also at some downstream facilities (like a networking repeater; just to maintain chlorine levels that would otherwise have fallen due to distance from the upstream chlorination site) Tolt: http://www.seattle.gov/utilities/your-services/water/water-system/tolt-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s... Cedar: http://www.seattle.gov/utilities/your-services/water/water-system/cedar-treatment-facility http://www.seattle.gov/utilities/your-services/water/water-s...

TedDoesntTalk 6y ago

Is there a health risk to consuming chlorine in water?