Are you asking about attaching a dripper hose to reuse the rainwater? If so I would not suggest this as it could cause a backup. Instead I would suggest a rain barrel which you could attach a hose to and the barrel will overflow with any excess water.
If you are talking about a roof water drain pipe to sewer it is illegal. If you are talking about a sink drain pipe well that is where they all connect to so yea.
There is a 4" hole for the inlet near the top of every properly made septic tank. You connect the drain to this by gluing if it's a plastic pipe or by a 'Robar' joint if it's a cast iron pipe.
Usually not, check with local authorities about codes on such matters.
A dehumidifier is a device for the removal of moisture from the air. The copper pipe that is not connected is almost certainly a drain pipe. As the dehumidifier removes moisture from the air, it has to collect and then drain in some way. A drain pipe would handle the latter chore. Consult the manufacturer or a distributor for a manual or just some information.
Weeping tile is used in landscaping and construction to manage and regulate excess water around a building or in a yard. It is also known as a French drain or perimeter drain. It comprises of a perforated pipe set in a trench with gravel or aggregate near the base of a building or in a designated part of a yard. When water needs to be redirected or managed, such as during heavy rains, weeping tile is used to prevent water from gathering around the foundation and seeping into the basement or causing other damage. It is also often employed in landscaping to prevent water accumulation in areas such as gardens, retaining walls, and similar features. Weeping tile, in its most basic form, is an effective method for avoiding water damage to structures and preserving outdoor areas.
Radio Shack "drain pipe tracer".
You must first connect a 1/2 inch PVC pipe to the outlet for the regeneration fitting on the softner and run this pipe outside and trench to the sewer drain and tie into sewer drain. The sewer drain will then flow the brine regenerater fluid to the septic tank.
Foul Air
Yes, a sewage drain pipe can be too large.
You want the drain pipe for a kitchen sink at least 18" above the floor. You do not want it any closer or it might be kicked, or damaged during building or installing the faucet pieces.
Every building has a "stink pipe." Usually located on the roof these pipes vent air to allow the plumbing drains inside the building to work correctly. As water flows into a plumbing drain pipe, air is vented out of the drain through the "stink pipe." The pipe that goes from the bottom of the back of your toilet, up the side of your house to let any gases produced by the waste escape into the air instead of bubbling back up through your toilet and sticking up your house.
dvw pipe = drain, waste and vent pipe.