Having a drain issue.  Main line is cleaned out but having slow drains throughout the house still.  I already snaked it myself and it is better but still needs help

I'd turn on each faucet separately and stop, then time the drain. Once you find the slowest drain, you found where the problem is originating around and needs looked at, as that drain is slowing down the flow of other drains working properly of going to the main drain.

 I remember once of needing to remove each bathroom sink/tub drain pipe to clean out at the stopper lever bar that goes through the drain pipe of each sink/tub in a split level 2 bath home trying to find a slow drain. Hair especially, catches on everything and plugs up over time when soaps also get involved then buildup over time.

You might also need to go onto roof and see that all air vent pipes are clear by looking down into with flashlight of any wasp nests/bird nest that may of broken up and fallen into pipe and will stop up air flow to different areas of the house drains. You'll have more than one air vent for separate areas like kitchen and bathroom(s).

Get back to us to say what you find. Hope it's simple, but seeing you have a cleared main drain, you got something slowing the air/water flow before reaching the main if everything worked great before.

Edited. Double posted.

Ya so all the drains are affected about the same.  They flow but slow.  My bath tube and washer are on the same floor and also the same line.  When it backs up you get small bits of black sludge after I snaked the line.  The sewer guy said there was some blockage on the "home" side and needs to be cleaned out.  The house is about 60 yrs old btw.

My home right now is 60+yrs old. I recently(past fall) had a very slow drain in my single bath sink. Some things, thank God were upgraded before I moved in by my parents and kin over time as my home belonged to my Grandparents when they moved in to it back in 1960.

 I had to remove (in basement) the sink's drain pipe that connected to the cast iron main pipe. The upgraded plastic pipe/rubber connection collars was clogged with things that should of drained out, but kept getting caught on the iron lips where it joined up to the cast iron main drain. It was black sludge at it's worse.

I used a catch pan to contain sludge, but it was still a mess after all the scraping I did to open the drain's hole back up. Hooked up things and turned on water to flush out any residue and all's well again.

If you still have all cast iron drain pipes going to cast iron main drain, I'm betting that over time you got some serious rust scale/sludge built up and you need to probably cut some drain pipe while leaving a 6" stud at the connection point of the main drain and put in some new plastic PVC white pipe with rubber hose collars as a remodel to help, as over time you'll need to clear it out again, as I have to mine.

Wish I could look at that but at last, my house is on a slab and all the pipes go direct into the concrete

Good suggestion though

Ok. Go to a home improvement store and go to aisle where they have septic drain cleaners. Get pure 100% crystallized lye (not that diluted liquid stuff), make pan of boiling hot water and put hot water in sink, then put dosage of lye and keep close watch for minute or so. It's gonna fizz heavily when it finds something and goes to work. It's gonna take some time, so all you can do now is let sit to work. Keep all kids and animals away---close door. Lock if necessary. Open window some to help clear out any fumes that might develop.

If it clears and you are on a septic system, pour in a gallon of vinegar to neutralize the lye. Put in new septic RidX after running some clean water if on septic system.

Even before you do all this, I'd still take things apart and clean out ALL sink's pipe traps and if sinks have the pull levers that drop a stop plunger into drain hole as the rods that go through the pipe always catch hair/debris that does more clogging than a turd in a toilet.

 I've done the lye method for my pipes and it does work, but before doing it I always uncouple/clean out/reconnect the trap pipes to be sure they're clear before proceeding to the nuclear option.

My guess is if all drains are slow you have a lateral line problem, if they are cast iron under slab they are probably rusted out on the bottom of the pipes. You need to have a camera ran down them to inspect the lines. Running a sink machine down them will only create more problems.

Snyder Plumbing and Heating in Platte City have been excellent.