We must however remember that pure RO water is not safe for health. Infact the fact that it removes almost all minerals makes it unsuitable for human consumption because the water starts extracting salts within body due to a salt concentration difference. For this reason, Plants of multinational companies strictly forbid use of RO water available in plant lines for any drinking.
Companies like Nestle and others follow a delicate process to add precise quantities of require minerals into RO water, Nestle then Ozonates the water so a few ppm of ozone keeps the water bactaria free(other companies use chlorine which can make mineral water taste 'karwa')
So-Safe RO costs around 40K with a mineral cartidge which you cannot trust until a proper lab analysis is performed.