48. This should preferably be below 750mm annually (which is the figure recommended by both ADAS and many of the other consultancies offering advice about pig farming) but rainfall must also be considered in relation to soil type and ground conditions. There are parts of the UK where annual rainfall exceeds 750mm but where the excellent soil composition allied to good management allow a unit to perform satisfactorily. Conversely, a marginal soil type is only likely to be suitable in an area of low rainfall and will be unacceptable where the rainfall is high. Clearly there is an important interaction between rainfall and soil types and we stress that careful site selection is the key to avoiding excessively muddy conditions. Provision of a suitable floor-board or waterproof cover over the ground inside the huts may be necessary on some sites.