Hard water is safe for ...

Hard water is safe for drinking and does not cause any health issues unless there is a high contamination level of metals like arsenic. The best way is to take the help of a TDS metre. The TDS metre helps you measure the TDS value in your water supply. As an average, a TDS value of more than 200 PPM in water makes it hard water. But it also depends on the other contaminants in your water. 

1. You could add a whole house sediment filter to your main line into the house. There are a couple different kinds (replaceable paper, cleanable metal screen, and more fancy options).
2. You could add a reverse osmosis system and significant size storage tank to store enough RO water since the system won't keep up.

"Water containing TDS concentrations below 1000 mg/litre is usually acceptable to consumers, although acceptability may vary according to circumstances. However, the presence of high levels of TDS in water may be objectionable to consumers owing to the resulting taste and to excessive scaling in water pipes, heaters, boilers, and household appliances Water with extremely low concentrations of TDS may also be unacceptable to consumers because of its flat, insipid taste; it is also often corrosive to water-supply systems "