Related by context. Frequent words. (Click for all words.) 69 rainwater harvesting 55 rainwater 54 Organic farming 53 xeriscaping 53 groundwater recharge 52 irrigation 52 composting toilets 52 drip irrigation 51 collect rainwater 50 flush toilets 50 lawn watering 50 xeriscape 49 watering lawns 49 cisterns 48 potable 47 potable water 47 Planting trees 47 conservation 47 micro hydro 47 stormwater pollution 47 seawater desalination 46 ecologically sound 46 biogas plants 46 composting 46 evaporative cooling 46 toilet flushing 46 Mulching 46 flushing toilets 46 water purifier 46 solar thermal 46 sewage disposal 46 Renewable energy 45 irrigating 45 waterless urinals 45 water 45 waste disposal 45 drought tolerant plants 45 irrigate 45 desalinization 44 stormwater 44 carbon sequestration 44 desalination 44 planting trees 44 outdoor watering 44 recycling 44 irrigated agriculture 44 Gasification 44 Desalination 44 potable drinking 44 nonpolluting 44 Composting 44 reduce reuse recycle 43 biogas 43 permaculture 43 renewable energy 43 afforestation 43 composters 43 desalination plants 43 cistern 42 drought resistant 42 Conserving 42 Environmentally friendly 42 membrane filtration 42 Reusing 42 forestation 42 Watering 42 flush toilet 42 borewells 42 groundwater 42 underground aquifers 42 paddy cultivation 42 Eco friendly 42 rainwater tanks 42 evaporative 42 reverse osmosis 42 environmentally sound 41 Solar panels 41 parabolic trough 41 solar panels 41 conserving 41 rainwater runoff 41 stormwater runoff 41 Solar PV 41 desalinated water 41 hydropower 41 arid regions 41 reservoirs 41 solar 41 solar photovoltaics 41 solar powered 41 Solar Thermal 41 organic farming 41 geo thermal 41 Biogas 41 WaterSense 41 anaerobic digesters 41 guzzlers 41 soil erosion 41 aerators 41 freshwater 41 wastewater