Sites for healthy people protect clean water and dispose of  dirty water well. This does not have to be expensive, if you plan with care!

Clean Water

Water from deep wells or rain is often safe to drink. Roof drains need first flush devices
to divert the dirty first rain if contains bird droppings or too much dust.

Surface water can be disinfected. Even if lake or stream water looks clear, it may need to be pumped through large filters, or treated with chlorine.

Systems in the developed world often use high pressure and expensive equipment. Pumped systems with intermittent electrical service often have pressure drops in the supply lines that let contaminants in. For people who hand carry their water, simpler systems may work better.

Three inexpensive ways to provide safer water for a family are SODIS (solar disinfection), a Slow Sand Filter, or ceramic cartridge filters. The tiniest is probably the LifeStraw, a filter in a drinking straw for an individual.
Even for small communities systems without pumps can be used. Solar cells and a small UV filter attached to a 5 gallon bucket can disinfect enough water for 15 families (with continuous power it could provide for 100 families a day).

For each of these clean water solutions users must learn to disinfect their containers
and to separate purified water from questionable water.

Hand washing with ash or clean water outside the latrine is important. A tippy-tap bottle lets people rinse hands using a simple foot control. Otherwise germs will be spread by the water bottle.
Below: Tippy tap

Greywater

Water from washing or showers has few germs. It may be as simple as dumping the dishpan over the plants, or taking a bucket shower on the edge of the garden.

Greywater from showers is usually clean, but if people wash clothes in the shower with diapers, it will carry dangerous disease bacteria. Run it under a mulch bed borderd by a raised lip.

From kitchens in the developing world greywater contains too much bleach, from kitchens in the developed world it carries too much grease.

Greywater stored for 24 hours smells. It can clog pipes with small holes. Clear illustrations show simple branched drain systems for disposal on Ludwig’s website.

Above left: Latrine raised above groundwater level

Above right: Squat toilet

Blackwater

Waste water from toilets carries disease germs. Where water is precious, squat toilets flushed by a bucket with very little water may be preferred. Latrines and composting toilets don’t use any water but often smell bad. Different cultures clean themselves differently and may want sinks in the toilet stalls.

Blackwater must go into the ground at least 30 m (100 feet) from a well, stream or lake. Septic pipes with holes laid in gravel trenches place the liquid 2′ (60 cm) deep in medium soil (not too sandy or too heavy clay). Many developing world places use a soakaway hole 2- 2.7 m (6- 8 feet deep). Latrines have a seat or squat hole on a floor above a soakaway pit. Often children are afraid to use latrines for fear old floors will collapse. These deep blackwater disposal systems may also contaminate groundwater.

Urine from healthy people usually has few germs. Where slums lack space for latrines, the biodegradable PeePoo bag can be sold and collected. Its dried ammonia disinfects solids, reduces smell, and within several months turns waste into good soil.

Below left: Concrete toilet made around bucket

Below right: Urine diversion for a composting toilet

Human waste is valuable to improve soil if it can be kept away from water supplies. Waste composts if urine is diverted, becoming safe in 6- 12 months. Some latrines have 2 chambers so waste ages before being removed and used safely for agriculture.

A shallow latrine called the arbor-loo is easier for a small family to dig. They put a light
enclosure around a small toilet floor. They must add straw or chips or ash to reduce the
smell. Every few months they dig a new hole, cover the waste hole with earth, and plant a vine or fruit tree on it. No one has to handle the waste.