There isn't a minimum really below a slab as long as you're below it. The locator must be reading the invert (bottom of pipe) so say if it's a 4” sch 40 pvc pipe then to get to the top of pipe it's safe to assume you're really 3” below.
Should be flush to the finished floor and bolted down. That's what all the holes are for in the flange. Screws are fine. If it's floating shim it with something suitable for damp locations, not because of leaks, but because it's a bathroom and bathrooms get wet.
The most important bit of obvious advice ever: soil and waste pipes need to be on a downhill gradient! The “fall” or “drop” should be between 1/40 (1cm down for every 40cm across) and 1/110.
For instance, residential sewer line depth ranges from 18 to 30 inches. However, city sewer line depths are different. Your city's sewer lines must always be deeper than the deepest residential pipe to allow waste to flow downhill. As such, these lines can go as deep as needed.
In general, pipe runs made of blue MDPE should be buried at least 750mm below finished ground level. In addition, they should be positioned 350mm from other pipes and utilities. Alternatively, they can be buried in a trench that is at least 300mm wide and as deep as the pipe itself.
Believe it or not, plumbing pipes under a slab house foundation is typically 12 to 24 inches deep. The pipes are installed into trenches and then buried before the rebar, wire mesh, and concrete slab are poured.
In general, the maximum distance of the toilet from the main drain should not exceed 4 meters, with a 2% minimum slope. Within these limits, the plumbing system can guarantee an effective draining, avoiding bad smells and the problem of emptying the siphons.
You probably know that drains need to flow downhill into your sewer. But do you know the proper slope? The ideal slope of any drain line is ¼ inch per foot of pipe. In other words, for every foot the pipe travels horizontally, it should be dropping ¼ inch vertically.
You will also need to make sure that the soil pipe sits a minimum of 200mm above the highest water entry point (aka the highest point where wastewater will reach within a soil pipe).
A typical plastic waste system (be it Polypropylene Push-Fit or ABS Solvent Weld) will be comprised of 32/40mm pipes and fittings connected to either: a 50mm pipeline that runs directly down into the drain.
Reasons to Caulk Around a Toilet
Moisture Prevention: Without caulk around the toilet base, external water can seep under the toilet, leading to floor and subfloor damage over time. This is especially important in bathrooms with wooden floors, as prolonged exposure to moisture can lead to rot and structural issues.
A toilet trap sounds like something you'd want to steer clear of, but it's actually a key component of a toilet drain that helps keep sewer gases out of your home.
The standard drain line size for a toilet is 3 inches in diameter, which is recommended to ensure proper drainage and prevent clogging. It's important to check local building codes for specific requirements, as they can vary by region. Storables provides a comprehensive guide on standard sizes and regulations.
Recommended Slope for Toilet Drain Pipes
An adequate slope allows gravity to effectively carry waste and water through the drain pipes and into the sewer or septic system. The universally accepted standard for a toilet drain pipe slope is a quarter inch per foot of pipe (1/4 inch per foot).
Wall-mounted Toilets
The rough-in distance in the newer homes from the wall to the center of the toilet drain is 12-inch, while, older homes have a distance of anything between 10- or 14 inches.
According to plumbing code, drain pipe has to be sloped a minimum of 1/4-inch per foot and a maximum of three inches per foot or vertical. A slope of less than 1/4-inch per foot will cause constant drain clogs and a slope of more than three inches will allow the water to drain without the solids.
A 4-inch horizontal drainage pipe's minimum slope is 1% to 2% (or 1/8 inch to 1/4 inch per foot). The pipe should slope downward 1/8 inch to 1/4 inch per foot for drainage and to prevent clogs.
Toilet drain pipes are usually 3 inches in diameter. Washing machines and laundry sinks generally need 2-inch drain pipes. Shower and bathtub drain pipes are usually 2 inches in diameter. Sinks usually require a 1.5-inch drain pipe.
The typical rule of thumb according to code requires you to run a horizontal pipe for no more than one-third of the total length. However, there are exceptions to this building code: If your minimum pipe size is increased by one pipe size, there are no maximum length limitations implied in the system.
This 110mm straight pan connector extension piece can be used to extend a toilet waste drain pipe. This can be cut to the required length, while the thick rubber seals provide great sealing properties.
The term "waste stack" refers to the large diameter pipe that runs vertically through the property connecting all the waste pipes into a single flow. A soil stack does the same thing for the property's soil pipes.
They can range in depth from 12″ to 30″ and can be as deep as 6+ ft. Often, it's only a matter of the environment and climate. They will bury the line deeper in extremely cold climates to prevent the pipe from freezing solid in the winter.
The trench should be about 18 inches deep and 9 to 12 inches wide.
Underground piping shall be buried not less than 18 inches below the surface of the ground unless otherwise protected.