I am trying to list some of the tips - which should be taken care while getting plumbing work done for new house.
I am still new to this - correct me where-ever I am wrong - or add your points.
Sanitary
1) use quality pipe - Supreme is what I have used
2) Lay separate pipe for waste water (bath,sinks,washing machine outlet) and sanitary (lavatory pits/IWC) - let both the pipes join at chambers
3) liberally have chambers constructed.
4) avoid un-necessary bends - use long bends where ever possible.
5) use rack system - where sanitary piles on outside wall is at about 1 inch above the wall.
6) use air pipes to vent out bad odor.
7) test the slope of pile on ground - so that waste can flow easily - I have also heard that too-much slope is bad , as drywaste may stick to pile when water moves fastly .
8) have correct slope (180 degree) for p-trap for sink and washbasin - bit of water should stay there always - to avoid smell.
Water-connection
1) OHT (use triple layer tanks) should be placed a min of 6 feet height from roof -
2) use 1 inch pipe for OHT delivery (main pile)- reduce it to 3/4 inch when it come to your floor - I heard this is to maintain good pressure in taps .
3) use good quality pipes - I have used Ashirwad.
4) avoid un-necessary bends - use long bends where ever possible.
5) do-not fully merge solar connection with geezer connection - use a valve to switch between solar water and geezer water -place it in bathroom. - there is another option to use electric connection near solar panel only ( not sure how) so that you can switch from solar to electricity during monsoon - which makes geezer unnecessary ! ( but there will some electricity loss)
6) if you can afford some more expenses - get separate connection for bore and corporation water - ( ie 2 OHT - one for bore water - one for corporation water , connect all non-drinking outlets to bore OHT)
Other gentlemen please share your thoughts/experience - so that plumbers can't take us for a ride
Regards