Use
the A1, rather than the M1 - going round Leicester
can be tedious. Take the A606 towards Oakham, and
after Empingham take left turn to Rutland Water north
shore. (Do not follow signs to Rutland Sailing
Club.)
If you use the M1, go to J21 Leicester, take ring
road to A47 then Uppingham. A6993 to Oakham, then
signs to Empingham and Whitwell.
Anglian Water website.