The case against "Full Cost Recovery" for water provision

Recently the UN recognized the human right to water. Sounds great! But who pays for it? The most conservative, hard-headed attempts to answer this question typically fall back on calls for water tariffs to be structured along the lines of "Full Cost Recovery." That too, sounds great. No subsidies; no outside loans; lean operations; the more you use, the greater your share of paying for it. Here's my problem: this system can be economically fair, but ecologically and socially disastrous. All parties can pay the service provision costs -- i.e. infrastructure, labor, insurance, capital, energy, repairs, maintenance -- and STILL deplete the aquifer or river itself, since water itself has no value. We can argue that "full cost recovery" need to include the cost of scarcity, or the cost of pollution, or the cost of lost aquatic habitat, or future generations deprived of clean and abundant water. But all THOSE costs are purely subjective; some call them 'externalities' but by definition they lay outside of all current forms of accounting by urban and rural water agencies are impossible to quantify in terms of objective 'costs'. This is important, because right now "full cost recovery" is advanced as the apex of resource management solutions to which all water agencies should aspire. By all means, cut subsidies and charge users based on a percentage of the costs of supplying water. But we should not pretend that 'full cost recovery' is in any way a sustainable solution, as long as water itself has no H2Ownership and, thus as a consequence, no measurable value of its own. Thoughts?