For most houses in Totton, the answer is yes, and without much drama. This is a town of ordinary post-war and later housing rather than a preserved historic core, which means the majority of homes here sit outside the tight controls that make extending a headache elsewhere. The heritage that does exist is real but contained: a modest set of listed buildings and three conservation areas, dotted about rather than blanketing the place. Buy a typical semi on a typical estate and your plans are a conversation with the planners, not a battle with history. Buy inside one of the protected pockets and the rules change, so the first job is working out which Totton you have bought into.
The listed buildings are few enough to name the constraint precisely. The town carries around thirty-four listed structures, none of them at the top grade, three at the middle grade of grade two star, and the remaining thirty-odd at grade two. Against a town of thousands of homes, that is a small slice, and it skews toward churches, older civic pieces and the odd historic curiosity like the tide mill rather than the average family house. If your home is one of the listed ones, listing bites hard: it covers the inside as well as the outside, and changes that would be routine anywhere else need formal consent before a single brick moves. Most buyers will never touch that regime, but the ones who do should go in knowing the freedom to alter is heavily reduced.
The conservation areas are the wider thing to watch. Totton has three of them, at Eling, Hanger Farm and Hazel Farm, and living inside one brings a layer of extra control that does not apply on the ordinary streets around them. Within a conservation area the usual permitted-development freedoms can be trimmed back, more types of work need consent, and the character of the street becomes something the planners will actively defend. It is not a ban on extending, but it is a longer path with more boxes to tick, and the estuary-side setting of Eling in particular is exactly the sort of place where that scrutiny is applied rather than waved through.
In practical terms, the split is clean. On the bulk of Totton's housing, standard permitted-development rights apply and a sensible rear or side extension is a manageable project rather than a legal saga. Step inside a conservation area or buy a listed home and you move into consent territory, where the sensible order of events is to check the designation for the specific address before you fall for the possibilities. The town gives you room to build in most places and asks you to slow down in a few, which is a fair trade rather than an obstacle course.
The verdict is a comfortable middle. Totton offers most homeowners genuine freedom to extend and alter, with the restrictions confined to a handful of listed properties and three conservation areas, so your scope depends almost entirely on which side of those lines your house sits.