The building inspector says we need to place a plug at the lower cleanout and fill the pipe from above with water to test for leaks I have the plug, is it wise to put in a plug where the toilet sits before testing

STOP!! Don't plug the cleanout and then fill the stacks. If you do you'll have water all over the place. Every sink, tub. Vanity, washer station and toilet will overflow.
Now I need the information you've left out. This is what we do on our 2nd, rough inspection. Is that what you have? A half built house with no fixtures installed or what? Let me in on what's going down. I need more information. Back to you, Tom

I have a modular home that has all sinks, toilets installed already. It is a rough inspection.The home is 15 years old and just moved it from a park to our own property.

Thanks for the info!!

OK! I understand. Here's what you're going to hafta do. Take a count of every fixture in your house that has a trap including toilets and floor drains, Now remove the bends from the traps and measure the openings. Now go to an plumbing supply house and tell them what you have to do and ask them to tell you what size inflatable test balls you'll need to seal off the drainage. Once you seal off all openings including the house cleanout you may go on the roof and fill the stacks. Leave it set overnight and call your inspection for the next morning. Good luck, Tom

I think you should talk to inspector. Ask him to tell you explicitly what he wants you do do. Better yet, talk to someone else in the office. Something doesn't sound right here.

Sounds right to me Harold,
The inspector's asking for a 2nd rough inspect. Sometimes called "A tub set and water pipe inspection. That's when we seal off the drainage and fill the stacks from the roof. We also pressure up the water pipes. This is done the night before the inspection so if there's any leaks they will show up the next day, This is a unit that's been disconnected and moved. Who knows what pipes were damaged or pulled apart during the move. Hence the static water test. Things a little clearer now? Regards, Tom

But this is a mobile home. Doesn't sound right to do a rough in inspection on mobile home. Sounds like inspector does not know that it is mobile home or is misapplying inspection requirements.
Could just be mis-communication problem or could be weird requirements of some jurisdiction.

I'd check with another individual in inspection office just to be sure.

But this is a mobile home. Doesn't sound right to do a rough in inspection on mobile home. Sounds like inspector does not know that it is mobile home or is misapplying inspection requirements.
Could just be mis-communication problem or could be weird requirements of some jurisdiction.
I'd check with another individual in inspection office just to be sure.
And you'd be entirely correct if this was, indeed a mobile home. But it's not!

I have a modular home Lots of difference between a nodular and a mobile home. Everything has tom be tested before the inspector can issue a CO. Regards, Tom

I stand corrected.