We are opening a small donut shop. We will need a source of "recipe quality" hot water for making the donut dough (raised donuts) and batter (cake donuts). A typical batch of raised donuts requires ~8.5 lbs of water (~1 gallon) that can range in temperature up to 90°F. (Water temperature for cake donuts can exceed 105°F.) We will be making multiple batches throughout the day. Some donut shops use an electric hot water dispenser (like used to heat water for coffee or tea) as a source of hot water for preparing the donut mix. However, this solution has several disadvantages: Requires counter space. No ability to use a water mixer/doser. Limited quantity of how water available at a time. Cost of the dispenser. Using a plumbed source of hot water would negate the first three disadvantages, and the overall costs would be reduced as well. Ideally, I would install a point-of-use (POU) tankless electric water heater just upstream of the mixer/doser. This would also allow us to install an activated carbon filtration system in the cold water supply just upstream of the POU heater. Unfortunately, the commercial space we'll be leasing only has 100A of electric service and a POU heater would draw at least 60A. Upgrading the electrical service to the shop is way outside our budget. The other option would be to use water from the tank-style water heater (which uses natural gas) already installed in the shop; this heater is like the typical water heater in most US homes. Normally, it's recommended to not consume hot water from a heated supply. This is mostly because of concerns of hot water causing more lead/chemicals to leach from pipes versus cold water. Certainly, this is a concern for plumbing installed prior to 1986, when copper pipes were joined with lead-based solder. Or for PEX pipe, which can leach more chemicals out of the plastic at high temperatures. But I would plumb the hot water pipe from the tank heater to the dough prep station using copper and lead-free solder. Also, the distance from the heater to the dough-prep station is very short and that pipe would also feed a nearby hand washing sink, so the hot water in the line would be constantly flushed throughout the workday. This would mean hot water flowing from the water heater to the dough-prep station would have very little dwell time in the pipes to leach anything. So the only real downside that I can see would be the inability to install an activated carbon filter on the hot water supply to the dough-prep station. However, the cold water supply to the dough-prep station will have carbon filtration so the final mixed-temp water for the dough will be partially carbon-filtered in proportion to the cold'/hot water ratio in use. And there will be a point-of-entry sediment filter for all the water coming into the shop, including the water supply to the tank water heater. Thoughts?