It varies street by street, and knowing which one you have changes how we clear it. Older Fareham — Wallington, Catisfield, Osborn Road, Highlands and the streets around Fareham Park — sits under heavy mature limes, sycamores and horse chestnuts, so the classic autumn problem is deep leaf mulch that composts into a solid, wet plug and then sprouts grass and seedlings by spring. Closer to the harbour and along the Portchester side, gull activity adds nesting material, feathers and bones, which mat together and hold water even when the leaves are gone. Damp, sheltered north-facing runs across the whole town grow moss on the roof tiles, and each heavy rain washes a caps' worth of that moss straight into the gutter, where it settles into a dense mat right at the outlet. New-build estates get a different one again: roof grit and cement wash from the original build, plus the granular shedding from newer tiles. Then there is the flat-roof and extension guttering common on Fareham's 1960s–80s stock, where a shallow fall means even a small amount of silt causes standing water and mosquito breeding through summer.