Helen Isherwood, of Willow Green, frequently walks across the Moor and was appalled to see litter, traffic cones and rusty bikes dumped in the water.
"At the moment it looks like a tip so people treat it as such," she said.
"Whilst the Moor is in this state Knutsford does not deserve to win any awards such as Britain in Bloom."
The pool - part of the Tatton Mere site of special scientific interest - is home to birds and rare water plants.
"I have seen many ducks swimming amongst the litter and I think it is terrible," said Mrs Isherwood.
"It is their home and they should not have to contend with rubbish."
Last week the Macclesfield Borough Council placed three benches overlooking the water, but the view for visitors is far from scenic.
"The council are making a real effort to make it a lovely place," she said.
"The benches are nice and in the summer it would be a lovely place to sit if you didn't have to look at litter, supermarket trolleys and rusty fencing."
The argument over who should clean the Moor Pool has raged for years.
On Monday town mayor Councillor Jennifer Holbrook said she was aware of the problem and had reported it.
"Unfortunately there are a number of people have no regard and so throw litter in the pool, but it is not acceptable," she said.
"There is a major emphasis on cleanliness for Britain in Bloom so the pool is a concern to us."
The Moor Pool is owned by Randle Brooks, but his agent at Meller Braggins was unavailable for comment this week.
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