another RO/DI question

[sphelps]

In Richmond you shouldn't need DI so I would avoid it all together since it'll just add cost to maintenance with little gain and it's a pain to change.

If you do go with DI the one will be more than adequate but you can go with three if you're planning on failing behind on filter changes as the extra DI will help.

For drinking water just tee a line in before the DI to your faucet or whatever. Just be sure to also have your pressure water storage tank also plumbed in prior to the DI. Also if it has a final polishing filter use that only on the drinking line.