Gday Petigram.
My performance inflight section of the Boeing QRH 700/800 series gives take-off speed data for dry,wet and slush/standing water above 3mm in depth. Only the slush etc is advisory. The dry and wet info backs onto each other and typically there is a 5 to 7 knot reduction across the range of T/O weights. The slush info has reductions of up to 23 knots in some scenarios, with weight considerations in addition.
Hope that helps.