Graywater Reuse in Other Countries and its Applicability to Jordan -- continued --

The Intermittent Nature of the Water Supply 

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The intermittent nature of the water supply already has been discussed. All municipal areas receive pumped water from the water authority for a limited number of days each week, varying (reportedly) from 1 to 4 days per week, depending on location and time of year. Each household stores the municipal water in tanks, either on the roof of the property or underground. Most low-income households have storage capacity of 1 m3 or 2 m3, which must be conserved so that it will last the 4 – 6 days until the municipal supply is restored. Because of this, most high water usage (e.g. floor washing and laundry) is confined to or at least occurs mostly during ‘water days’. Consequently, the production of graywater is low during no-water-supply days, peaking significantly during water-supply days. This uneven production of graywater will have an effect on how graywater is stored and used. Ideally, the use of graywater for irrigation should be fairly evenly dispersed throughout the week. In an extreme case, a household that effectively produces all its graywater during the one day when the water supply is on will need to store this graywater in order to provide a balanced delivery of water for irrigation. The higher cost of providing this storage, in comparison to a household that only needs to store graywater for 3 days, may be significant.

The Low Cost of Water

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The real costs of water supply and distribution in Jordan are not passed on to the domestic consumer – particularly the low-end consumers. This provides a disincentive to conserve for the low to medium income user. Current domestic water tariffs increase with usage, and those for Amman are summarized in the table below.

Table 4.2:  Current Water Prices in Amman

These low prices reduce the effective ‘financial savings’ to be made by reusing graywater, particularly by low-end consumers. 

Variation in Income

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The large economic disparity between high income and low income households in Jordan affects the ability to purchase water, with high income users being able to afford large underground tanks in which to store municipal water, and also to supplement municipal water supplies through purchase of water from privately operated water trucks. Lower income households cannot afford these methods and must make do with the limited available water supply. 

These differences are expressed in per capita water use. The moderately affluent families of Amman have lifestyles comparable to Europe and the US (having baths, western toilets, irrigated gardens, cars in need of washing, etc) with corresponding per capita water use of 300 – 400 liters/person/day, while people in rural areas (having neither the same water use requirements, nor the means of storage and supply) make do with perhaps as little as 60-70 liters/person/day (Iskandarani 1999).

4.4   Current Legislation in Jordan Regarding Graywater Reuse

The Jordanian regulations governing household plumbing are the ‘Sanitary Wastewater System Code’, and the ‘Water Supply Code’ (Ministry of Public Works and Housing 1988). These codes provide guidelines for the design and installation of plumbing systems in domestic properties. The Water Supply Code provides guidelines for the supply of hot and cold water to buildings including fire fighting systems.  This code has little or no relevance to graywater reuse and plumbing.

The Sanitary Wastewater System Code provides guidelines for internal and external drainage and wastewater systems, and gives recommendations for pipe types and dimensions and for design of rainwater gutters. It provides extensive design guidelines for septic tanks. The codes suggest (2/4/2, page 20) that all wastewater should be discharged using a sanitary wastewater system in accordance with the recommendations laid down in the code, and prohibits wastewater discharge according to any other method. There is no explicit prohibition of the installation of a separate plumbing system for graywater. On the contrary, it is recommended that the toilet, bidet and urinals should not be connected into the same pipe as the floor drains and sinks, until outside the building. A suggested layout (page 85) for a domestic wastewater system shows the wastewater from the toilet and bidet being kept separate from the shower and sink until outside the building where they are connected at a manhole.

The code requires that each pipe joint, bend or change in level outside the property is facilitated by an access chamber (manhole). The code also suggests (page 85) that each bathroom has its own external manhole, and requires (page 62) wastewater to be discharged into the municipal drain where possible, and failing this, to a septic tank.

Although graywater reuse is not expressly permitted, many of the above requirements – if implemented – could facilitate the use of graywater. A governmental committee recently has been formed to examine the codes in light of the potential for graywater reuse, and to propose amendments that would allow the reuse of graywater more easily, in particular to require all household plumbing to separate graywater from blackwater until outside the building.

Jordan Standard 893, Reuse of Wastewater for Irrigation

This standard regulates the quality of treated wastewater that may be used in irrigation in Jordan. The code generally is applied to the reuse of treated wastewater – blackwater - from municipal wastewater treatment plants. It is arguable that the guidelines given in this code may not be relevant to the small-scale use of graywater in a domestic context, given the vast difference in the quantities involved. The parameter levels set in the code are for the protection of the health of both agricultural workers and consumers of the irrigated produce, and also for the mitigation of impacts on the environment, in particular degradation of the surface water and groundwater resource, due to the large-scale use of treated wastewater.

4.5   Economic Factors

The Individual Consumer

There are two aspects to the economic picture in relation to graywater reuse. The simpler one concerns the individual household consumer. A domestic consumer has a particular annual water requirement. For the water supplied to him, either by the Water Authority of Jordan (WAJ) or a private supplier, he pays a charge. This charge is dependent on the water use – the tariffs were presented in table 4.2.  

If a component of the supplied water can be reused, a reduction in the amount of water purchased by the household will result, and a financial saving may follow. However, a capital cost is associated with the introduction of a graywater reuse system (for example additional pipes, treatment, etc), there will be a period of time before this capital cost is ‘paid for’ through savings in water bills. The amount of time this takes will depend on the initial cost of the system, the amount of water saved by reusing the graywater, and the water tariff. For households in the lowest tariff, there will be no direct monetary saving as a result of lower water usage. For large user households, particularly those with a large irrigation demand, the savings may be significant enough to make the cost of installing a graywater system worthwhile in the medium term on purely economic grounds.  

For households whose water income is limited not by earnings but by supply constraints (i.e. who use all the water they can get, and who could pay for more water if they could get it), the result will not be a financial saving, but a release of an amount of additionally available water for their household use. This may prove to be a more motivating factor than a straight saving in water bills. Such a household may be able to put off the expense and effort of installing (for example) an additional storage tank by reusing their graywater.

The Big Picture

However, it is upon looking at the bigger picture that the potential advantages become more significant. Jordan’s annual water supply deficit was outlined in Chapter 1. Even investment in additional collection, storage and distribution infrastructure will not eliminate the gap in Jordan’s water needs. Restructuring the water sector institutions may help increase the efficiency of distribution and cost recovery, but will not actually provide more water. Management and reduction of the growing demand must play its part.

It has not yet been established that graywater reuse on a large scale will be feasible or achievable in Jordan. There are technical and other issues that need further investigation before graywater reuse can be widely promoted.  Also, the direct financial incentives to the low-use domestic consumer are minimal. However, other countries have demonstrated a significant overall reduction in domestic demand as a result of graywater reuse, and there is no reason to assume that significant demand reduction is not achievable in Jordan. The cost of producing this demand reduction is difficult to estimate – clearly in such a decentralized solution, there is an inefficiency or duplication in infrastructure. However, depending on how graywater reuse is implemented and funded, there may be significant hidden savings arising from the mobilization of a hidden resource of householders who would implement and maintain their systems at no cost to the Water Authority. Large-user households will see a reduction in water bills - a saving which will increase as the real costs of water are passed on to the consumer in the form of increased tariffs. Low-user households also will benefit, less in the direct financial saving, and more in the increase in the amount of water available to them, at minimal cost. The Water Authority of Jordan is best placed to put a monetary figure on what this demand reduction saving is worth, but it may be significant.

Graywater reuse is an increasingly common household practice in a number of arid countries, and, in some areas, is practiced whether legal or not. A range of technical solutions are available, and there are simple ways to minimize the adverse impacts on plant and human health. An increasing number of authorities are beginning to permit and regulate graywater reuse. 

There is every reason for householders in Jordan, with its increasing annual water deficit, to examine how best graywater reuse can be implemented in their homes. This report has presented ways in which graywater is reused in other countries. This CSBE study will go on to study the practical reuse of graywater in Jordan and will develop and publish advice and guidance on how best to reuse graywater for garden irrigation safely and economically.

Prepared by Stephen McIllwaine

© 2003