I know people should not drink distilled water alone, I am considering using it in conjunction with other sources. My well water has a very high level of TDS (1200 mg/L), and the current water system only trades calcium for other minerals. A reverse osmosis system is not practical due to low water pressure and lack of funds. EPA recommends a TDS level below (500 mg/L).

What I propose is to use distilled water only when planning to use a "sports additive" like HEED. Are any commercially available mixes going to give me a good mineral profile? I do have a big tub of HEED still to use.

Alternatively, should I use 25-50% well water to get a more "normal" TDS level, and use my mix of choice?

I cannot help but notice that on your post, just to the right of it and even above, is an advertisement for reverse osmosis systems. How clever.

We have a fancy multi-cartridge system that goes to a separate spigot on our kitchen sink. It takes out chlorine and fluoride, too. Even our house plants and sourdough starter are doing better. We use it for all our potable water.

Just buy a Zero Water pitcher and filters like I did.

According to their site, each $14 filter would get him about 3.75 gallons of filtered water. They mention something like 22.5 gallons life for 200 TDS.

If his dissolved solids aren't ionic, he might be better with a regular old carbon filter or a 3 stage under the sink. With ionic contaminants, filtration even on a large scale is expensive (I used to use deionized water; you get a big tank for a filter, the size of a scuba tank, but it's pricey and I don't know the cost comparison).

The first thing to do is sample your water and send it off to get a water profile. Find out what's in it.

I have a water cooler. $100 investment up front from Lowe's and $.39 per gallon for reverse-osmosis filtered water at the local grocery store. Cold and Hot water right out of the spigot.

What you're missing out in calcium, fluoride and other minerals in distilled water can be more than made up for with a healthy diet. I disagree that the minuscule amounts of additives you consume from tap water can make you any healthier.

If you have high TDS and low water pressure, there are RO units out there that are specially designed to address these issues. I imagine a 3 stage pre-filter, booster pump and a decent RO unit will be able to last several years if well maintained. I only have ~330ppm TDS and decent water pressure so I run a basic RO unit that's still producing <10ppm TDS water after 3 years of service with only basic pre-filter changes. Check out the spectrapure line - they are more expensive than the ebay no-name brand units but they are very extremely well built.

If you're taken by the RO scam, you're low on something other than water pressure...

An industrial scale RO system is under 50% efficient. A home scale RO system with all the bells and whistles can just break 10%; some of them are under 6%. That means 90% of your water just gets dumped down the drain. Of course since you're using well water, your only concern is power usage (running the RO) and flow availability (the well does eventually run out if you overdraw).

Also, water molecules are bigger than i.e. Fluoride ions, so you can have fluoride in your output. Says some chemical engineering master's student, but I suspect he's wrong (my minimal high school chemistry credentials tell me that the electrical bonding between dissociated fluoride salt ions would prevent the fluoride ions from flowing through the RO membrane). Everything else comes out, for sure.

I just think RO wastes a lot of accessed water.

Current system is three pre-filters and a salt brine flush softener that flushes itself every seven days. Before the pre-filters, we'd get pieces of shale in our tap water regularly. An under the sink system would have to be in addition to existing system. The other plumbing fixtures will foul within a year without the softener.

I am assuming you live in the south west, these systems are not marketed in my area. I can get water service, but it is much more expensive.

Who says not to drink distilled water? You get nutrients from food, not water. The purest and cleanest water is the best. Distilled is pretty much the purest you can get for water, and treated with UV, gets rid of bacteria etc...which is usually part of any water treatment process/purification.

If you want minerals, flouride and other nutrients, take a multi-vitamin, brush your teeth with flouride toothpaste, or eat better foods.

I live in the southwest...corner of Michigan about 6 miles from Lake Michigan.