Tokyo Tap Water

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
Mike-R

#1: Post by Mike-R »

Anyone in Tokyo have an opinion on the quality of Tokyo tap water for espresso machines? I'm relatively new to the subject of water quality for espresso, so I am posting here in the hopes that someone based in Tokyo has already looked into this.

Not sure if it helps, but here is an interesting article about water hardness in Japan.
https://www.nature.com/articles/s41598-021-92949-8

DanoM

#2: Post by DanoM »

I'm in Hokkaido, so I've never dealt with Tokyo water for espresso.

According to Tokyo Water the hardness depends on season and ranges from 50~100mg/l. 100mg might be a little hard and you'll get some scale build up, but manageable. Flavor of Tokyo water is more likely an issue, and you'd probably want some kind of filter system to deal with that, which in turn could also remove some of the hardness too.
https://www.waterworks.metro.tokyo.lg.j ... qa-13.html
https://www.waterworks.metro.tokyo.lg.j ... 0%20mg%2FL

Tokyo has been dealing with summer drought conditions for some time now, and my guess is that would lead to harder water during the dry period. Less flow generally means higher mineralization.
LMWDP #445

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homeburrero
Team HB

#3: Post by homeburrero »

Mike-R wrote:Not sure if it helps, but here is an interesting article about water hardness in Japan.
https://www.nature.com/articles/s41598-021-92949-8
Excellent article! It does help with the water hardness levels in Tokyo:


It does indicate a total hardness range in the 55 - 85 mg/L ballpark. If you assume that the calcium hardness as well as the carbonate alkalinity is lower than the total hardness, which is reasonable, you have water that has low scaling potential. If you wanted assuredly non-scaling water I think you would want to soften.

Unfortunately this article and the Tokyo waterworks site give you no idea about alkalinity. Nor about chloride ion, or silica. I doubt there is an issue there, but If either of those last two were high then you might need to resort to RO treatment. Tokyo does disinfect with chlorine, but that's easily handled by simple activated charcoal or carbon block filtration.

P.S. The Tokyo waterworks' water quality FAQ has this statement:
Q; How can I find out the results of water quality examinations?
A; The Bureau of Waterworks ensures the safety of tap water through regular water quality examination. The results are published on our website, collected in the "Annual Water Quality Report", and supplied to Citizens Information Rooms and other places.

But I was unable to locate anything resembling an annual report.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

Marmot

#4: Post by Marmot »

The main problem is flavour as DanoM already suspected.
Last time I was in Tokyo I took some coffee tools with me and tried out different beans from shops and roasters. There is a lot of great choices in Tokyo!
But in the beginning the coffee I brewed somehow tasted off and it stayed the same with different beans. It took me quite long to realize that the problem is the chlorine in the tap water I was using. When I switched to bottled water the coffee tasted so much better!
I am quite blessed with the tap water I get here in Switzerland which tastes great and has an almost ideal hardness. For that reason I never really doubted using tap water for my coffee.
So the problem is the chlorine. But I think if you reside at the border of Tokyo it might be that you get mountain spring water. Most will taste of chlorine though and you will also have to go for bottled water.

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homeburrero
Team HB

#5: Post by homeburrero »

Marmot wrote:So the problem is the chlorine.
Pretty much any tap water will have chlorine or chloramine added as a disinfectant, which can seriously affect taste. Chlorine will dissipate in an open container, and it is easily removed by activated charcoal or carbon block filters. Most modern refrigerators with an ice water line have a filter that removes chlorine. Pitcher filters like Brita will also do the job. Tokyo uses chlorine, but some utilities use chloramine, which may require more contact time to remove - you can get filters that are optimized for chloramine removal.

Of course bottled water, or recipe water based on minerals added to purified water is always a safe option, especially important in cases where you are unsure about what is in your tap water. You can even use that option in plumb-in cases with a carboy and Flojet-like system: Espresso Cart - Goodbye Plumbed In

In some locations it's hard to find good purified or bottled water in large or refillable containers. Not sure if that's true in Tokyo. I understand that there is a Tokyo-sui bottled water available in Japan, which is just Tokyo tap water in a bottle.

P.S.
If you want to avoid needing to periodically descale, and want to fill your reservoir with charcoal filtered tap water like Tokyo water, which is not very hard but possibly will drop some scale, then you can use a reservoir pouch like the Rocket or Oscar/Bilt to soften the water. Replace it every 6 months and make a habit of refilling the reservoir at the end of the day so that newly added water has overnight contact time with the softener pouch. On some machines you can use a softening filter that fits the intake hose in the reservoir.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

Mike-R (original poster)

#6: Post by Mike-R (original poster) »

DanoM wrote:I'm in Hokkaido, so I've never dealt with Tokyo water for espresso.

According to Tokyo Water the hardness depends on season and ranges from 50~100mg/l. 100mg might be a little hard and you'll get some scale build up, but manageable. Flavor of Tokyo water is more likely an issue, and you'd probably want some kind of filter system to deal with that, which in turn could also remove some of the hardness too.
https://www.waterworks.metro.tokyo.lg.j ... qa-13.html
https://www.waterworks.metro.tokyo.lg.j ... 0%20mg%2FL

Tokyo has been dealing with summer drought conditions for some time now, and my guess is that would lead to harder water during the dry period. Less flow generally means higher mineralization.
Thanks. At the very least I plan to use a good water filter that should remove flavor issues including chlorine.

Mike-R (original poster)

#7: Post by Mike-R (original poster) »

homeburrero wrote:Excellent article! It does help with the water hardness levels in Tokyo:
image

It does indicate a total hardness range in the 55 - 85 mg/L ballpark. If you assume that the calcium hardness as well as the carbonate alkalinity is lower than the total hardness, which is reasonable, you have water that has low scaling potential. If you wanted assuredly non-scaling water I think you would want to soften.

Unfortunately this article and the Tokyo waterworks site give you no idea about alkalinity. Nor about chloride ion, or silica. I doubt there is an issue there, but If either of those last two were high then you might need to resort to RO treatment. Tokyo does disinfect with chlorine, but that's easily handled by simple activated charcoal or carbon block filtration.

P.S. The Tokyo waterworks' water quality FAQ has this statement:
Q; How can I find out the results of water quality examinations?
A; The Bureau of Waterworks ensures the safety of tap water through regular water quality examination. The results are published on our website, collected in the "Annual Water Quality Report", and supplied to Citizens Information Rooms and other places.

But I was unable to locate anything resembling an annual report.
The report and website seemed the same way to me too... tantalizing but not complete. When I make it to Tokyo, I'll probably end up going with filtered tap water and an in-tank softener like I am using now. Or if I purchase a home, I'll plumb my machine and install an in-line water softener.

Mike-R (original poster)

#8: Post by Mike-R (original poster) »

Marmot wrote:The main problem is flavour as DanoM already suspected.
Last time I was in Tokyo I took some coffee tools with me and tried out different beans from shops and roasters. There is a lot of great choices in Tokyo!
But in the beginning the coffee I brewed somehow tasted off and it stayed the same with different beans. It took me quite long to realize that the problem is the chlorine in the tap water I was using. When I switched to bottled water the coffee tasted so much better!
I am quite blessed with the tap water I get here in Switzerland which tastes great and has an almost ideal hardness. For that reason I never really doubted using tap water for my coffee.
So the problem is the chlorine. But I think if you reside at the border of Tokyo it might be that you get mountain spring water. Most will taste of chlorine though and you will also have to go for bottled water.
Indeed, there is a lot of good espresso in Tokyo these days.

I find the taste of Tokyo water to be pretty good after a carbon filter. But I understand it's all relative and I do recall the water tasting great when I visited Switzerland a few years ago. :D

Mike-R (original poster)

#9: Post by Mike-R (original poster) »

homeburrero wrote:Pretty much any tap water will have chlorine or chloramine added as a disinfectant, which can seriously affect taste. Chlorine will dissipate in an open container, and it is easily removed by activated charcoal or carbon block filters. Most modern refrigerators with an ice water line have a filter that removes chlorine. Pitcher filters like Brita will also do the job. Tokyo uses chlorine, but some utilities use chloramine, which may require more contact time to remove - you can get filters that are optimized for chloramine removal.

Of course bottled water, or recipe water based on minerals added to purified water is always a safe option, especially important in cases where you are unsure about what is in your tap water. You can even use that option in plumb-in cases with a carboy and Flojet-like system: Espresso Cart - Goodbye Plumbed In

In some locations it's hard to find good purified or bottled water in large or refillable containers. Not sure if that's true in Tokyo. I understand that there is a Tokyo-sui bottled water available in Japan, which is just Tokyo tap water in a bottle.

P.S.
If you want to avoid needing to periodically descale, and want to fill your reservoir with charcoal filtered tap water like Tokyo water, which is not very hard but possibly will drop some scale, then you can use a reservoir pouch like the Rocket or Oscar/Bilt to soften the water. Replace it every 6 months and make a habit of refilling the reservoir at the end of the day so that newly added water has overnight contact time with the softener pouch. On some machines you can use a softening filter that fits the intake hose in the reservoir.
One of my constraints in Tokyo is the size of apartments. I will probably not have space for bottled or recipe water, so my water source will probably be filtered water from the refrigerator. Refrigerator filters tend to have activated carbon and should clean up any chlorine taste. Thanks for the tip about chlorizine optimized filters, I will look for that.

I'm still on the fence about softening. I had used a dual boiler espresso machine for 5 years in Tokyo before descaling, and the water came out clear. I assume that means there was no scale buildup.

If I do go with a softener, I will probably use an in-tank softener for space reasons. If I buy a house, I will probably plumb my machine and install an in-line softener.

User avatar
homeburrero
Team HB

#10: Post by homeburrero »

Mike-R wrote:Refrigerator filters tend to have activated carbon and should clean up any chlorine taste.
Yes.
Mike-R wrote:Thanks for the tip about chlorizine optimized filters, I will look for that.
For Tokyo, which just uses chlorine, you should not need any chloramine-optimized filter. They work fine for chlorine as well as chloramine but would cost you more.

Mike-R wrote:When I make it to Tokyo, I'll probably end up going with filtered tap water and an in-tank softener like I am using now.
Sounds reasonable to me for limescale risk. To be confident about long term corrosion risk it would still be good to know how much chloride ion is in that Tokyo water.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h