The soil disturbance produced by a range of trenchless drainage tines, working under different soil conditions, is described and the effect of the different types of disturbance on subsequent drainage system performance considered. Few problems are likely to arise with trenchless tines working above critical depth. Below critical depth, impeding layers may develop alongside the pipe, reducing drainage efficiency in groundwater control situations, and lack of crack development above the pipe may impede water flow in top-water problem areas. Soil conditions most susceptible to damage are highlighted and methods suggested for avoiding, alleviating and minimizing potential problems. The study suggests trenchless drainage installation techniques can be used with confidence over a wide range of soil conditions, providing care is taken and in some cases, modifications made to the technique.