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Water from Hot Water Tank

Is there a downside to drawing brew water initially from my house hot water tank? This would shorten time to the boil.

New Brewer on my first batch and planning the next one. Thanks.

I’ve heard that it’s never really a good idea to use “house” hot water for cooking or drinking. Hot water sitting in the tank and lines can leach small amounts of things into the water (lead being one of them). I’m sure the amounts are very small, and I don’t have any specific studies to quote, but I’ve always just thought it wasn’t worth risking. Hopefully our resident water expert, Martin, will see this post. I know he’ll have more specific and helpful info.


I always use hot water from my hot water tank (city water) because my HLT is 25 gallons. I have had no issues and won many awards with my beers. Once I made my beer with bottled water just to see if there was a difference and there was none. YMMV

It does matter how new your water heater and house piping are. In the US, EPA has put in place regulations that severely limit the amount of lead or other bad things in the piping and fixtures in contact with our drinking water. But there are a LOT of homes that have older piping and fixtures. So understanding how this issue affects their water is important.

The most important factor regarding lead exposure is the character of your tap water. This is where a hard and alkaline water supply is a real plus. Alkalinity in the water is helpful in protecting against lead exposure due to a chemical reaction that carbonate has with lead. Lead carbonate forms where those ions combine and they form a relatively impermeable barrier to further lead exposure.

A really soft and non-alkaline water like those found in the Pacific Northwest (RO and rain water too) are very corrosive to metals, including lead. If your water supply falls in this category, you need to be aware. Water Utilities that have supplies like this often inject lime or phosphate into the water to help reduce its corrosivity to piping and fixtures.

So if these protective coatings of lead carbonate or lead phosphate are in place in your water system, the temperature of the water has little effect on the leaching of lead. But if your water falls in the soft and non-alkaline category, then heating the water can increase the leaching of lead from your system. The other thing that heating does is reduce the carbonate content of water by driving out CO2. So a marginal water with a little carbonate may become more corrosive with heating.

Since lead is present in such small amounts in typical piping and fixtures, the concentrations that leaching produces are exceedingly small. There is no way that you would ever know (taste) that a typical water had lead in it. However, since lead is a heavy metal, it accumulates in your body. A few nanograms of lead per glass of water (or beer) would add up over a lifetime of consumption. So it is important to avoid lead as much as possible.

Unless your water is really soft and non-alkaline, there is little reason to avoid using hot water for cooking or brewing.

PS: there are sources that state that you shouldn’t drink hot water. But my review of those sources indicates that they are citing cases where the water is soft and non-alkaline.

Thanks for such comprehensive replies.
Experienced brewers that take the time to share their knowledge make this forum very useful. Especially for new comers who are isolated from metro areas where a club might exist.

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