No, one pump only, your main supply should flow directly to the water tank. Then, from the water tank, you use water pump to distribute to your bathrooms, kitchen and etc.

Actually, for older design, most of the developer use main supply for outdoor as well as the kitchen. But, this would cause inconvenience whenever there is a water disruption. So, for me, i change the design. My main goes directly to two big tanks. Then, from these two tanks my pump distributes. So, even if there is water disruption, my kitchen and outdoor garden are not affected as my supply in the tanks is able to sustain for 5 days.

Honestly, water directly from main is techinically non-potable. I have to use a battery-power timer to flush out the dirts accumulated inside my water filter everyday.

Just for your information, my main contractor also told me about the risk of bacteria. I did some research, this is one example of information available
https://dwi.gov.uk/consumers/learn-more-abo...s-and-cisterns/
I observed most of the requirements as stated in the above website.