"Security is a real benefit enjoyed by those who reside here," say the agents - they're talking about the fact that it's part of a gated community.
But this three-bedroom property is secure in a different way too, having been used as an air raid tower during World War II.
Built in the eighteenth century by French prisoners from the Seven Years War, the 110-foot tower is situated on the former site of the Royal Naval Hospital in Plymouth.
Originally a water tower, it was converted into a home seven years ago, and is now for sale for offers over £600,000.
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"Under the watchful eye of the local conservation office, the property was painstakingly and lovingly restored to an extraordinarily high standard throughout, some seven years ago and converted into a bespoke residence with a surprisingly practical flow of accommodation," say agents Mansbridge Balment.
"Many of the original materials have been retained, with the old limestone walls being in evidence through much of the accommodation, whilst the original lead lined, wooden water frame for the water tanks has been retained."
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The house is a lot more practical than you might expect. There's a large kitchen/diner taking up the ground floor of the original octagonal building. There's also a good-sized sitting room which once housed a donkey, walking around to power a windlass that raised and lowered a bucket for water.
Meanwhile, a garden room, study, utility and shower room - as well as a sauna - are housed in a modern extension.
Above, there's a master bedroom with en suite, and two more bedrooms above. At the top, doors open to a terrace, with fantastic sea views of Drake's Island, Plymouth Sound and Mount Edgcumbe.
Beneath the house, there's a 'leat' - an underground watercourse - which was once used as an escape route by press-ganged sailors.
Now, though, it's not so easy to get in and out. "High limestone walls surround the site, which has a single, amicably and dignified, controlled entrance, resulting in an entirely unique security climate," the agents say.
That's something that swanky buyers may appreciate, as the house isn't in the poshest part of town.
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Outside, there's a good-sized garden, thanks to the previous owners who bought an extra patch of land. There's also a patio area with a hot tub.
"The moment I saw The Water Tower, I knew that I just "had to have it! I saw in it potential 'wow' factor, which frustrated my husband as he could not envisage downsizing to such an individual home," says the current owner.
"I'm sad we have to part with it, but I know that it is truly an exceptional home."