Yes. A reduction fitting can be used.
I would use 3 inch for that.
A sewer "rod" is normally no larger then 3/8 of an inch diameter BUT a SEWER Cable can be as large as 11\4" even the small sewer rods can have large heads to maintain sewers as large as 36"
In Tulsa Oklahoma you can, but i would still use 4 in.
By placing the waste 2x the diameter above the opening
1/8" to 1/4" inch per foot.
A 3 or 4 inch pipe sticking straight up out of the ground? This is the clean out for the sewer line. If sewage is coming out of it, this means the sewer line is clogged or collapsed from there to the main city sewer. If you have a septic tank, the tank is full and needs to be pumped out.
For sanitary sewer lines in commercial buildings, the minimum slope depends on the pipe diameter, as set by plumbing codes like the International Plumbing Code (IPC) or Uniform Plumbing Code (UPC): Pipes 2.5 inches (65 mm) or smaller: minimum slope is 1/4 inch per foot (≈ 2.08%). Pipes 3 inches (75 mm) to 6 inches (150 mm): minimum slope is 1/8 inch per foot (≈ 1.04%). Larger pipes (8 inches / 200 mm or more): slope can be 1/16 inch per foot (≈ 0.5%), if allowed by design and code. This slope ensures wastewater flows fast enough to prevent clogs but not too fast to leave solids behind.
The maximum slope for a 3-inch sewer pipe is typically recommended to be 1/4 inch per foot (approximately 2% slope). This ensures adequate flow and prevents blockages while allowing for proper drainage. However, local building codes or regulations may vary, so it's essential to consult them for specific requirements in your area.
In an inch, there are 16 lines. It should be the 12th line. From line 0 to line 12 is 3/4 an inch.
The standard sizes for toilet water supply lines are typically 3/8 inch or 1/2 inch in diameter.
i prefer 12 inch