The Corporations of both Manchester and Liverpool had already constructed a series of reservoirs to support their growth (Liverpool at Rivington, Manchester at Longdendale) but saw no possibility of further reservoirs there.
 Concerned that their existing water supplies would be rendered inadequate by their growth, they were now seeking further supplies: to comply with the Royal Commission's "no poaching" recommendation any further reservoirs would have to be much further afield.
In 1875 John Frederick Bateman suggested that Manchester and Liverpool should supply themselves with water from Haweswater and Ullswater (made reservoirs) as a joint undertaking.
Both Liverpool and Manchester Corporation rejected this, feeling that the interests of their city required its water supply to be independent of that of any other city.
Instead in 1877, Liverpool initiated a scheme for a reservoir on the headwaters of the Vyrnwy in North Wales; at the instigation of their chairman (a native of Cumberland with a second home at Portinscale on Derwentwater), the Waterworks Committee of Manchester Corporation  proposed to supply Manchester with water from a Thirlmere reservoir.
 
In their report to the full Council, it was noted that water consumption had been 8 million gallons a day in 1855, 11 million gallons a day in 1865, in 1874 18 million gallons a day on average with peak demand 21 million gallons a day.
The reliable supply from the Longdendale reservoirs in periods of drought was only 25 million gallons per day, but in the last two years demand had increased by 2.4 million gallons a day.
Demand therefore was predicted to exceed the reliable supply in about seven years; it would take at least that to bring any major additional water supply on stream.
Any major new works should aim to secure adequate supplies for the next thirty or fifty years; these could only be found in the mountains and lakes of northern Lancashire, Westmorland or Cumberland.
Only Ullswater, Haweswater and Thirlmere were high enough to supply Manchester by gravity flow; the natural drainage of all three was to the north, but Thirlmere lay immediately below the pass of Dunmail Raise and the engineering to bring its waters south of the watershed would be significantly easier than for (for example) Ullswater.
Thirlmere water had been analysed by Professor Roscoe who pronounced it superior even to that of Loch Katrine and thus one of the best waters known.

Speaking to the report, the chairman of the Waterworks Committee noted that the catchment area  was over 11,000 acres (in which there were not more than 200 inhabitants) and the annual rainfall about 110 inches; fifty million gallons a day could be collected and sent to Manchester; unlike the massive dams in Longdendale, all that was needed was a wall fifty foot high across a gorge he could throw a stone across.
As regards aesthetic objections: "he was himself a native of the district where this water was to be found, and … there was no man living who would protect the beauties of the scenery with greater ardour and zeal than he would, but no man with common sense would say that in the works they were contemplating they were destroying any of the beauties of the place"
The report had predicted little opposition to the scheme, by which it asserted the "beauty of the lake will be rather enhanced than otherwise".
Other councillors were less sure of this, one noting that "they were going for a scheme which however they might gloss it over themselves, would arouse an amount of feeling on a question of sentiment of which the council had little conception, and therefore they must prepare for a very heavy parliamentary contest"
The Corporations of both Manchester and Liverpool had already constructed a series of reservoirs to support their growth (Liverpool at Rivington, Manchester at Longdendale) but saw no possibility of further reservoirs there.  Concerned that their existing water supplies would be rendered inadequate by their growth, they were now seeking further supplies: to comply with the Royal Commission's "no poaching" recommendation any further reservoirs would have to be much further afield. In 1875 John Frederick Bateman suggested that Manchester and Liverpool should supply themselves with water from Haweswater and Ullswater (made reservoirs) as a joint undertaking. Both Liverpool and Manchester Corporation rejected this, feeling that the interests of their city required its water supply to be independent of that of any other city. Instead in 1877, Liverpool initiated a scheme for a reservoir on the headwaters of the Vyrnwy in North Wales; at the instigation of their chairman (a native of Cumberland with a second home at Portinscale on Derwentwater), the Waterworks Committee of Manchester Corporation  proposed to supply Manchester with water from a Thirlmere reservoir.  
In their report to the full Council, it was noted that water consumption had been 8 million gallons a day in 1855, 11 million gallons a day in 1865, in 1874 18 million gallons a day on average with peak demand 21 million gallons a day. The reliable supply from the Longdendale reservoirs in periods of drought was only 25 million gallons per day, but in the last two years demand had increased by 2.4 million gallons a day. Demand therefore was predicted to exceed the reliable supply in about seven years; it would take at least that to bring any major additional water supply on stream. Any major new works should aim to secure adequate supplies for the next thirty or fifty years; these could only be found in the mountains and lakes of northern Lancashire, Westmorland or Cumberland. Only Ullswater, Haweswater and Thirlmere were high enough to supply Manchester by gravity flow; the natural drainage of all three was to the north, but Thirlmere lay immediately below the pass of Dunmail Raise and the engineering to bring its waters south of the watershed would be significantly easier than for (for example) Ullswater. Thirlmere water had been analysed by Professor Roscoe who pronounced it superior even to that of Loch Katrine and thus one of the best waters known.
Speaking to the report, the chairman of the Waterworks Committee noted that the catchment area  was over 11,000 acres (in which there were not more than 200 inhabitants) and the annual rainfall about 110 inches; fifty million gallons a day could be collected and sent to Manchester; unlike the massive dams in Longdendale, all that was needed was a wall fifty foot high across a gorge he could throw a stone across. As regards aesthetic objections: "he was himself a native of the district where this water was to be found, and … there was no man living who would protect the beauties of the scenery with greater ardour and zeal than he would, but no man with common sense would say that in the works they were contemplating they were destroying any of the beauties of the place"
The report had predicted little opposition to the scheme, by which it asserted the "beauty of the lake will be rather enhanced than otherwise". Other councillors were less sure of this, one noting that "they were going for a scheme which however they might gloss it over themselves, would arouse an amount of feeling on a question of sentiment of which the council had little conception, and therefore they must prepare for a very heavy parliamentary contest"
Thirlmere