Question:
I always drink the distilled water freshly made at home except when I buy it from Guardian, NTUC, or Cold Storage, which is still reasonably fresh, as it is unopened. ideas?

Answer: Not being in Singapore I can only speculate. The water quality problem seems an opportunity for some enterprising businessman to import resin based water softener systems and see how they will solve the problem. These are whole house systems (CDN$600+?) that are a must for rural homes that draw well water high in iron or high in other dissolved minerals that damage the plumbing. The ion exchange resin removes many minerals from potable water. This may be enough to improve Singapore's tap water. If not try adding a membrane filter system to the resin system. The resin is recharged by rinsing it with rock s

There you are, a business opportunity, either self contained whole house units or better, as a supplier of large container bottled water for the home. That is the new business supplies 20 litre (larger?) bottles of drinking water for the home.The office type bottled water cooler for the home is becoming very popular in N America. Water cooler models cost between $80 to $150 and provides refrigerated water as well as hot water or room temp. water. Beats boiling your own water and storing them in an air pot or whatever.