we've replaced the pipes under the tub, toilet, and sink. along with the washer, replaced the traps and also, cemented the end sewer pipe that wasn't capped off, when the house was switched to city sewer. now there is odor that doesn't go away. we smell it every hour. and when it rains and when it's too hot or muggy the smell is worse. we have kids in the house and a new born. please help.
smells are difficult to diagnose. check all the traps, make sure they're full of water. Any mechanical fittings (clean out caps, ferncos, ect) make sure are tight. A smoke test is the best way to find leaks in a drainage system. You cap all cleanouts that aren't trapped, cap all vents but one, place a smoke bomb like this http://www.defensedevices.com/commando-smoke-bombs.html into a metal coffee can inside of a shopvac and blow the smoke into the one remaining open vent. Any leak in the drainage system will leak smoke. the only problem is that it might be in a ceiling or behind a wall. if you're not comfortable with this, you should be able to find a professional in your area that does it