We just bought our first house they ran a new sewage line from all sinks,toilets,tubs,and washer to main line and replace main line to city main. The main bath sink is the worst it smells my sons room and hall way. Is the pipe to small main is 4in and vent is 2in. We have 2 full baths with sinks,toilets,one tub/shower,and one shower in other one. Kitchen has dishwasher,garbage disposal, and laundry room next to it. Kitchen is farthest away and vent in middle of pipe run and trap at beginning of run before it leaves house. What worries me is first toilet don't flush well at all. Last week we had a slight problem over thanksgiving both toilets overflowed and was clogged we tried running snake through cleanout opening but was unsuccessful. We ended up pulling both toilets and kitchen sink trap to run power snake through. Now drains flow, main toilet flushes fine but sinks still stink and front toilet don't flush well its mounted correctly and main acting up again. Ran a toilet snake through both toilets. This house is a plumbers dream all cpvc pipes 2in off hot water heater one hanger for 20 ft. runs 2or more butt connectors at every fixture with no or very little hold downs main tub outlet is cpvc and broken off once that I know of. Was planning all to renew water supplies with copper and correct amount of hold downs next month but now its on hold another month till I fix drains

We just bought our first house they ran a new sewage line from all sinks,toilets,tubs,and washer to main line and replace main line to city main.

How long ago did you buy the house and was a plumbing contractor used to do the replacement?

The main bath sink is the worst it smells my sons room and hall way.

Could be a clogged vent line or a sewer leak under the house

Is the pipe to small main is 4in and vent is 2in. We have 2 full baths with sinks,toilets,one tub/shower,and one shower in other one.

That is standard size and should have no problems carrying the load of baths.

Kitchen has dishwasher,garbage disposal, and laundry room next to it. Kitchen is farthest away and vent in middle of pipe run and trap at beginning of run before it leaves house.

Not sure what you mean here.

What worries me is first toilet don't flush well at all.

How old is the WC? What name brand is it? Could be as simple as the water jets are not all the way open or something could be hung up in the WC

Last week we had a slight problem over thanksgiving both toilets overflowed and was clogged we tried running snake through cleanout opening but was unsuccessful. We ended up pulling both toilets and kitchen sink trap to run power snake through.

So the clogg was under the house and not in the yard? Again was a contractor used to do the replacement work?

Now drains flow, main toilet flushes fine but sinks still stink and front toilet don't flush well its mounted correctly and main acting up again.

Check and see if the problem is on the city side of the line…when it was tied in it may not have been done right and that is causing the problem.

Ran a toilet snake through both toilets. This house is a plumbers dream all cpvc pipes 2in off hot water heater one hanger for 20 ft. runs 2or more butt connectors at every fixture with no or very little hold downs main tub outlet is cpvc and broken off once that I know of. Was planning all to renew water supplies with copper and correct amount of hold downs next month but now its on hold another month till I fix drains

I would suggest using pex to replace the water lines…it does not freeze and has a 25 year warranty. It is also cheaper to buy and easier to use….. Hope this helps.