On new housing estates it is often caused by compacted soil as a result of builders diggers and dumpers etc driving over garden areas before fencing goes up. This combined with the mixing of sub-soil and topsoil when all the trenches and foundations were excavated often leads to a heavy, wet plot, with very little top soil sometimes only an inch thick.
In cases where new estates have been built on old arable land that has been cultivated annually for centuries, a "plough pan" may have developed. This is an impervious layer of more compact soil just below the maximum ploughing depth, caused by years of polishing by the sole of the plough.
Of course, drainage problems need not be caused by any human activity, the soil may by its nature (e.g. clay soils) be water retentive or, if it is low lying, be affected by the natural water table of the area.