I’m in a Chicago suburb so we have pretty decent municipal water from Chicago.

I’m re-piping the entire house and installing a tankless hot water heater.

1.) Thinking about installing a spin down flushable sediment filter while I’m at it. They are relatively inexpensive and seem to be low maintenance. I get a lot of sediment now when I shut water off but I think most will go away once I scrap the old galvanized pipe. Not sure at this point what else comes from the service line or street.


2.) Would you guys recommend a pre-treatment to prevent scale build up? I’m installing the flush valve kit so I can flush the unit with vinegar but would one of those Venturi based units make sense?

We had a tankless in our old house and the plumber that installed it also installed a sediment filter on the cold input line. He explained that the passages are extremely small inside the heater, that's how they get such fast heat transfer and hi efficiency, and once they clog up they are nearly impossible to clean. Vinegar may be OK for mineral scale, but won't help with inorganic particles like rust and sand.

We used a 30 micron whole house sediment filter and changed the cartridge every 4 months. I can't find the pic right now, but the filter cartridge had a rusty sludge in it, looked like mustard. House was 100% copper pipe, city supply, but must have had some old iron mains somewhere in the system. Rust particles were very fine and hadn't ever noticed any discoloration before we added the filter.

So definitely add a filter.

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Not a plumber by trade but a fierce DIYer