design (such as the addition of ventilation piping to the feces vault) have been developed in many countries. prefabricated ceramic or plastic urine diversion squatting pans and pedestals have become available on the market, generally increasing the durability and perceived prestige associated with the system. uddts have also been commercially produced in sweden since the mid-1990s. for example, between 1994 and 2010 the separett company sold approximately 200,000 uddts. numerous off-the shelf commercial products are now available and are used in locations where a connection to a sanitary sewer system is not possible, permitted or desired such as in remote summer cottages or for camping activities. at all times, users have also been building their own low-cost uddts with simple materials such as a funnel connected to a hose, a bucket and a seat. examples south africa (ethekwini municipality, durban) the highest number of uddts in one area have been installed by the ethekwini municipality in the non-sewered peri-urban areas of durban, south africa. to date, about 80,000 uddts are in operation in that area, serving about 500,000 residents (reuse of urine or excreta is currently not taking place). haiti the ngo soil in haiti began building uddts and composting plants in port-au-prince as part of the 2010 haiti earthquake emergency relief effort in northern haiti. they have since branched out into providing toilets for residential use, this being their primary goal moving forward as they transition their focus from emergency relief to providing sustainable and ecological sanitation for paying customers. their current dry toilet design for households includes a small portable single vault unit made out of wood that is either fitted with a single container for combined excreta collection or with a urine diversion insert, with 80% of these installations currently being of the uddt type. as of 2014, soil has transformed all of their public uddt vault toilets to an open vault design with removable plastic drums for feces collection. this improves the processes by which feces is collected and transported to their waste treatment facility, making their business now a fully "container-based system". this allows soil to respond to heavy use (since their toilets were filling up too quickly) and ensures a safe final product for reuse. in most cases, these uddts utilize soak pits (normally located directly beneath the toilet superstructure) for onsite disposal of urine. a soil truck delivering buckets of human excreta from mobile household uddts to the soil composting facility in port-au-prince, haiti soil continues to provide humanitarian relief in some of haiti's most vulnerable communities – notably those that have been particularly impacted by the cholera epidemic – by providing free access to public container-based uddts for over 3,500 people. in addition, over 2,000 people are currently accessing a soil "ecosan toilet" through the "ekolakay" business pilot, with a growing waitlist of people wanting to join, thus demonstrating the market demand for affordable sanitation, even in the world's most economically impoverished communities. since building the first waste treatment facility in haiti in 2009, soil has become one of the largest waste treatment operations in the country. soil's two composting waste treatment facilities currently transform over 20,000 gallons (75,708 liters) of human waste into safe, organic, agricultural-grade compost every month. the compost produced at these facilities is sold to farmers, organizations, businesses, and institutions around the country to help finance soil's waste treatment operations. ecuador hundreds of uddts have been built in ecuador to date. the various models in use adapt to different preferences, budgets and conditions, and the need to sometimes transport materials to remote locations by small airplanes. many of these uddts serve indigenous communities who live along small rivers as well as ecotourism operations in the amazonian part of the country. in these regions, piped water supply is often lacking, clay-rich soils do not permit infiltration of wastewater, and the groundwater level is usually high. these factors make other types of toilets or other forms of excreta management problematic. for example, local governments and ecotourism operations often install flush toilets that drain straight into rivers or into holes in the ground, where the water is intended to drain but cannot, since the soil is mostly impermeable clay. coupled with the abundant local rainfall, these pits tend to fill very fast and overflow into the nearest streams. the streams get easily contaminated with fecal matter, as they are often quite small and there is not much dilution with clean river water. this leads to health hazards for the communities who use these rivers for drinking water, washing, swimming, and fishing. namibia in namibia a type of uddt was developed which is locally called the "otji toilet". this uddt also uses the coandă effect to divert the majority of the urine into a trough at the base of the pedestal and from there into an infiltration area. between 2003 and 2011 about 1,200 otji toilets have been installed in the south of namibia and the rural areas around the otjiwarongo district. using the same design, the ngo ecosur has built "otji style" uddts in ecuador and el salvador since 2007, where they are called "inodoro seco". other countries the ngo women in europe for a common future (wecf) and local partners have built urine-diverting dry toilets for schools in eastern europe, caucasus and central asia (eecca region) in areas that lack a reliable water supply and waste management. in el alto, bolivia the ngo fundación sumaj huasi has constructed nearly 1000 uddts for 4500 persons, and is carrying out communal composting for the excreta collected. boating, recreational vehicles and camping for the boating community, it can also be an interesting alternative to convert from conventional nautical toilets that store waste in blackwater tanks, or immediate discharge overboard, to a uddt. three such uddts designed for nautical and recreational vehicle (rv) use (but not limited to these uses) are marketed in the united states, canada, australia, new zealand, the u.k. and some parts of the european union under the brand names "c-head" toilet, "boonjon" toilet, "nature's head toilet" and "air head toilet". camping: leave no trace is not only a philosophy but a necessity in areas where human waste left behind will not decay naturally. there are now models of uddts available (for example by the swedish company separett) that allow feces to be collected and packed out. only urine is left behind, which is of less concern as urine is nearly pathogen free. society and culture floor and roof of a low-cost uddt in ecuador demonstrating the use of a low-cost uddt in pumpuentsa, ecuador. general hurdles for acceptance there are several barriers to a wider acceptance of this technology: the technology is not well known yet, buying uddt components can be difficult, and in general it is difficult to finance sanitation services for the urban poor who rely on on-site sanitation.: 2 existing, affordable piped water supply and sanitary sewer infrastructure may also be an impediment to widespread adoption of uddts, as their existence not only removes two of the main drivers for uddts but also represents a significant public investment. many users do not have an interest in handling their excreta, which can be another hurdle for acceptance of uddts. provisions can be made to offer door-to-door/curbside collection of these materials, similar to how existing municipal or private schemes collect household organic waste (from kitchens and gardens, etc.) and transport these materials to a centralized facility for composting or biogas generation. number of users the exact number of people using uddts worldwide is unknown, but a rough estimate by giz (german development cooperation) in 2012 based on known projects in 84 countries put the number at approximately 2 million people. use of dried feces the international association of plumbing and mechanical officials (iapmo), a plumbing and mechanical code structure currently utilized by many western states, has recently proposed an addition to its "green plumbing mechanical code supplement" that "outlines performance criteria for site built composting toilets with and without urine diversion and manufactured composting toilets". if adopted, this new far reaching composting and urine diversion toilet code (the first of its kind in the united states) will appear in the 2015 edition of the green supplement to the uniform plumbing code. several u.s. states currently permit disposal of feces from uddts or composting toilets (usually a clear distinction between different types of dry toilets is not made) by burial with some mandating lesser minimum depths, as little as 6 inches, and others not specifying any minimum depth at all. for instance: the commonwealth of massachusetts requires that "residuals from the system must be buried on-site and covered with a minimum of six inches of clean compacted soil". in oregon the applicable regulations state that "humus from composting toilets may be used around ornamental shrubs, flowers, trees, or fruit trees and shall be buried under at least twelve inches of soil cover". rhode island acknowledges that "solids produced by alternative toilets may be buried on site", but specifies that "residuals shall not be applied to food crops". the department of health of the commonwealth of virginia requires that "all materials removed from a composting privy shall be buried", and that "compost material shall not be placed in vegetable gardens or on the ground surface". the state of vermont permits users to dispose of the byproducts via "shallow burial in a location approved by the agency that meets the minimum site conditions ". the state of washington takes a wholly different tack in choosing to model its extensive regulations that oversee the use of dry toilets (what it refers to as "waterless toilets") in large part on the federal regulations that govern sewage sludge. for dry toilet users in the united states (which includes users of uddts), an important distinction to keep in mind—and one that is supported by the aforementioned existence of numerous state regulations which make no mention of, and also diverge widely from, the requirements of the federal regulations that govern the management of sewage sludge—is that as long as the excreta in question is not ever referred to as "fertilizer" (but instead simply a material that is being disposed of) the federal 503 rule, known colloquially as the "epa biosolids rule" or the "epa sludge rule", has no jurisdiction over the byproducts of a dry toilet and that all oversight of these materials falls to the individual states. use of urine at present reuse of urine as a fertilizer in the united states is still in the conceptual phase. studies into its feasibility are currently underway in brattleboro, vermont, and are being conducted by the not-for-profit rich earth institute. perhaps accordingly, a quick review of the pertinent regulations in existence in several different states turns up zero mentions of "urine diversion" and zero mentions of urine specifically as a standalone material which requires distinct oversight. instead, when it is mentioned, it is always in conjunction with feces (as in the contents of a composting toilet or other non-source-separating dry toilet type. at least one state specifically regulates "liquids" produced but not recycled by a composting toilet (which could be construed as referring to urine) but the fact remains that none of the states surveyed distinctly uses the word "urine" when referring to "liquids". it is expected that as urine diverting toilets grow in popularity states will respond by amending their existing regulations to account for urine diverting toilets and also urine as a separate and distinct waste or resource stream. moreover, plans are currently underway to finalize a uniform plumbing code that would "represent the first codified requirements for the safe installation, maintenance and use for in any installation". gallery a urine-diverting toilet in a timber frame structure