One of the UK's most prestigious bottled waters, Hildon Natural Mineral Water is served at the House of Commons and the Royal Opera House (and is rumored to be the water of choice at Buckingham Palace). Hildon begins as rainfall, which percolates through the chalk hills of the Hampshire countryside. After a period of 50 years the water emerges at an underground aquifer beneath the nineteenth-century Hildon Estate. The chalk acts as a unique natural filtration system, protecting the water from pollution and endowing it with high levels of calcium. Once it reaches the source it is immediately bottled without chemical treatment. Naturally low in sodium, the water is prized for its purity and well-balanced taste. Hildon, which produces both still and sparkling varieties, was the first company in the world to sell a natural mineral water with a carbonation level below 2.9. This low level of carbonation makes their "Gently Sparkling" water ideal for sipping alongside fine wines and subtly flavored dishes, which risk being overwhelmed by more robust bubbles.