As noted in the introduction, the WUO, as an organizational form, is a tried and trusted concept. Furthermore, not only is there a long and widespread tradition of specific WUO legislation but, as highlighted in this paper, such legislation is often relatively detailed.
A number of key themes emerge. First of all, it is clear that there is no single model for WUO legislation. Nevertheless, despite differences in terminology and legal form, the basic approach taken by the legislation reviewed is remarkably similar. In the various countries considered, WUOs are democratically controlled and funded by their participants through very similar internal structures. They operate on a non-profit basis and are required to focus on specific water management tasks. These fundamental similarities transcend geographical, economic and cultural divides, as well as the strikingly wide range of tasks undertaken by WUOs in different parts of the world. Put simply, WUOs that undertake drainage as their main task operate in a manner that is very similar to WUOs that undertake irrigation and this similarity is reflected in the legislation.
To some extent this may be a result of history: no law exists in a vacuum and in this connection the ongoing influence of European legal approaches, largely a legacy of colonialism, should not be under-estimated. Yet at the same time WUOs, as evidenced by for example the Balinese Subaks that function on the basis of customary law, pre-date European legislation. Numerous other examples exist of informal and customary WUOs that have developed without the assistance of formal law. Strikingly, however, such WUOs tend to operate in much the same participatory manner as those foreseen in specific WUO legislation. Therefore, while the form of WUO legislation will certainly depend greatly on a country's history, it is highly arguable that the basic content and approach is of generally universal application.
This may not be as grand a claim as it first appears. Given the very nature of water as a resource - fluid and not easily subject to private ownership or control - and the fact that all WUO activities relate not only to water but also to the land of their participants then the legislation may simply reflect common sense. In other words, the only realistic and sustainable management approach is on a local, self-funding and participatory basis.
In this connection, a key feature of WUO legislation is the fact that, notwithstanding the level of detail it often contains, it is ultimately permissive. Most of the important practical legal rules, including the operating rules as well as those rules that determine the service to be provided and the level of charges, are determined at the level of the WUO, the level of the community. In the language of Legal Pluralism such rules would be characterized as 'local law'. The key issue is that within the framework provided by national legislation, local law is given formal backing by the state. Legislative provisions that confer substantive rights on WUO participants and which impose procedural obligations on WUOs that promote democracy and transparency have as their main objective the protection of individual WUO participants rather than an attempt by the state to control how WUOs function. In other words the effect of such rules is to protect ordinary WUO participants from those richer or more powerful members of the community who might otherwise seek to influence the functioning of the WUO for their own benefit. After all local law, like customary law, is subject to socio-economic factors and as such it is not necessarily inherently equitable.
In this context, further investigation would be merited on the relationship between WUO legislation and the operating rules established by WUOs themselves, both in countries with a long tradition of WUO legislation as well those in which the WUO is a relatively new concept.
While there are clearly many similarities in the legislation, there are also many differences. At first sight, one important difference is the legal form of participation, namely whether it is on a membership basis or not. In practice, however, this difference does not appear to be particularly significant. It is true that the legislation often does not require non-membership WUOs to have a general assembly. Yet many of the other legal rules and principles (such as those that relate to the allocation of votes) apply equally to membership and non-membership WUOs. The key issue here is that WUOs that do not function on a membership basis can only be established under public law.
This question of legal status - whether a WUO is established under public or private law - is in fact the difference that probably has the greatest effect, not because it has much practical impact on the basic internal operation of a WUO, but rather because of its effect on the relationship between a WUO and third parties. In short, special powers and privileges can more easily conferred on those WUOs that are established under public law. As seen in Part Twelve, the existence or otherwise of such powers and privileges can have a major impact on the ability of WUOs to fulfil their mandate. This is particularly true in the case of tax issues, as the existence or otherwise of a liability to pay and/or collect taxes can have a major impact on the economic viability (and thus the sustainability) of a WUO. As mentioned above, the problem here is that the relevant legal rules are invariably contained in national tax legislation rather than WUO legislation. A comparative study of the tax treatment of WUOs in different jurisdictions would be helpful in making the policy case for conferring tax exemptions on WUOs in those countries where they are, or will be, newly introduced.
Another area which reveals important differences of approach is that of regulatory oversight. All of the legislation reviewed provides for some form or other of regulatory oversight of WUO activity. The variations appear in the scope and form of such oversight and the degree to which the WUO regulator may influence a WUO's activity on a routine basis - for example through the power to approve decisions taken by a WUO or even to appoint or participate in the appointment of officers.
The next question that arises is how to evaluate the effectiveness of the WUO legislation described in this paper? This can be a difficult task, which can probably only be answered on a country by country basis by comparing the legislative provisions with the reality of WUO performance. As an area of future research, detailed country studies of both the legislation and its practical application would certainly take forward the process of analysing and understanding WUO legislation in a comparative context. By its nature, however, such research would need to be multi-disciplinary, combining a rigorous analysis of the legislation with a review of the economic, technical and institutional performance of WUOs in each selected country. After all, the existence of perfectly drafted legislation on the statute books is of little contribution if that legislation is not implemented in practice. Furthermore, although this paper describes legislation from some thirty jurisdictions, WUOs and WUO legislation exist in other countries in respect of which it has not been possible to obtain information. Again, further research would help to create a more complete picture of WUO legislation.
Finally, the WUO concept is well proven. With the probable effects of climate change including an increasing demand for water coupled with growing pressures on water quality as well as an increased risk of flooding, it is not hard to envisage en expanded role for WUOs. Ostrom describes the process whereby 'Water Replenishment Districts' were first established in California as a result of pressure on aquifers due to over-abstraction. Such bodies were granted a wide variety of powers to raise funds through a property tax - and to a lesser extent by a pump tax - to undertake measures to replenish an aquifer. But as we have seen, as well as conserving scarce resources, WUOs can also work to protect land against flooding and water-logging. Here too, climate change may well lead to a greater role for WUOs, with an appropriate legislative response. Further research into and analysis of WUO legislation will therefore be both useful and timely.
 Including the names
by which WUOs are described in the legislation.|
 An influence that may be perpetuated through technical assistance programmes.
 The most obvious example being the basic civil law/common law distinction.
 Whether landowners, occupiers or users.
 See for example Bruns, B.R & Meinzen Dick R.S.(eds) Negotiating Water Rights (2000) ITDG Publishing, London.