Drain Investigation: Drains are tricky to access and often out of sight, which means the real cause of the blocked drain isn’t always obvious.
Having to investigate your drain can often be an awkward and confusing task, and you can never guarantee you’ll find the course of the problem without the use of specialist tools to make your life easier.
The term drainpipe broadly encompasses a wide range of applications and purposes, both inside the house and outside. This makes the terminology misleading. Inside, drainpipe is that which empties plumbing fixtures and with the aid of gravity funnels waste down to a single point of exit where elevation is lowest. As tributaries join the main line, the diameter grows. (To some, the term drain piping means that it doesn’t transport solids, whereas waste piping means that it does.) Occasionally vent piping, the purpose of which is to equalise air pressure in the drainage system, doubles up as the drainpipe for fixtures on higher floors (a frowned-upon practice).
Outside, drainpipe is used to connect effluent house plumbing with the septic system or sewer. It is also what is used to carry storm water runoff from downspouts to a collection point or daylight away from the foundation. Most drains use it to dry out over saturated regions. Though the various professions dealing with these functions overlap with each other, drainpipe terminology is used in all of them.
Investigating drainage issues in homes may involve inspecting leaks, traps, vents, or floor drains. The cause of a clogged drainpipe might be the wrong type of trap, insufficient slope, double trapping, or a malfunctioning vent. Odours suggest that the water seal of a trap has been siphoned off (either from being an S-type or from excess pressure) or that it has evaporated, which happens in floor drains that are rarely used. There are many potential sources of leaks, including damaged or cracked drainpipe and corroded drain pipe fittings.
Investigating issues outside typically begins with an assessment of wet areas, particularly near the foundation. Gutters and downspouts are checked to see if they connect to a closed drainpipe system that removes storm water from foundation proximity. (Without proper drainage, soil saturates and hydro static pressure mounts; if severe enough, foundation walls can crack, tilt, or bow.) The closed drainpipe system should terminate in a rain garden, a retention pit, or daylight. Outside conditions should be compared with crawl space findings to get a complete picture of how storm water is being managed.
The investigation may extend to additional items such as sump pumps. Most drains are constructed by digging sloped ditches, filling them with gravel, and lining them with perforated drainpipe. High water tables, underground springs, leaks, and lack of a foundation drainpipe system can all cause standing water in the crawl space. This should be drained away naturally by gravity if possible, but when the house is in a bowl, the only option is a sump pump.