Water quality & potability

What the machine tolerates — silt, sand, salinity, hot water — is a different question with its own field guide: Silt, salinity & chemistry.

Protecting the source

Start with the reassuring part: a ram adds nothing to the water. The delivered flow is the same water that entered the drive pipe, pushed up by a pressure spike in a closed pipe. There is no fuel, no lubricant, no additive, and no contact with combustion products. The waste stream is the same water again, simply spilled.

So the delivered quality equals the source quality — and everything that can go wrong happens either at the intake, in the storage tank, or in the pipes. Those are all things you control.

Source protection is the cheapest treatment

No amount of chlorination reliably fixes a contaminated source, and every problem that reaches the tank is harder and more expensive to deal with than the same problem a kilometre upstream. Protect the catchment before you treat anything:

• Keep animals out. Fence the area around the intake and the spring eye. Livestock waste is the dominant source of faecal contamination in rural supplies, and a fence is far cheaper than a disinfection regime.
• Think about what is upslope. The intake protects the point of abstraction; it does nothing about a latrine, a cattle yard or a road drain 200 m up the hill. Walk the catchment above the intake before you commit.
• Prefer a spring or a protected seep. Where the source emerges from the ground it is filtered by soil and far less variable than a surface stream. A ram works well on a spring-fed intake with a small forebay.

Intake and forebay

The intake is the one place where the ram's own plumbing touches the water, so it is worth detailing properly. Draw from below the surface but above the bed: surface water carries leaves, oil and floating contamination, and bed water carries silt that will erode your valves and cloud the tank. A screened intake box with a settlable forebay behind it gives you three things at once — protection from debris, a place for sediment to drop out, and somewhere to clean without touching the ram.

• Fit a removable screen with mesh small enough to exclude fish and leaf litter but coarse enough that it does not clog weekly.
• Make the forebay easy to drain and clean, because you will clean it more often than you expect.
• Keep a first-flush diversion: after heavy rain, route the first dirty runoff away from the intake rather than through it.
• Keep the waste-water outfall well away from the intake, the forebay and the tap stands — and away from where people and animals will stand.

Treatment, storage and testing

If the source is protected, most schemes need no treatment at all beyond settling and sensible storage. Where the source is not protected, or where the supply serves people with particular vulnerability, treatment becomes a system with three stages that must happen in order.

1 · Settle and filter first

Disinfection works badly in cloudy water: particles shield organisms from chlorine and from ultraviolet light, so turbid water can carry a healthy chlorine residual and still make people ill. Settling in the forebay and the tank, then a slow sand or cartridge filter, is the step that makes everything after it work. Target turbidity below 5 NTU — ideally below 1 — before you disinfect, because both the chlorine demand and the shielding effect climb steeply with turbidity.

2 · Disinfect — pick the method the community can sustain

For a tanked supply, chlorination is the usual choice because it is the only cheap method that protects the water after treatment, deterring regrowth in the tank and the main. The targets are long established and come from the WHO drinking-water guidelines: for effective disinfection there should be a free chlorine residual of at least 0.5 mg/L after 30 minutes of contact time at a pH below 8.0, while the residual at the point where people collect water should sit at 0.2–0.5 mg/L. That second figure is the one you manage day to day — a pool test kit is enough to run a chlorination programme, and it tells you far more useful things than a once-a-year laboratory sample.

3 · Keep it clean to the tap

Treatment at the tank is undone by an open tank and a leaky main. The measures are simple and mostly free:

• Seal the tank with a fitted lid and a screened vent; fit a floating or high-level outlet so you draw from the cleanest water, with a washout at the floor for flushing sediment.
• Clean the tank at least annually, and always after any contamination event or major repair. Drain, scrub, rinse, refill — and do not leave cleaning water in the supply.
• Insist on food-grade, pressure-rated pipe — PE, HDPE or uPVC for potable use. Avoid unknown or reused pipe, and avoid lead-containing fittings and old lead-soldered joints. Note that a pipe rated for the ram's delivery head is not automatically rated for a gravity main further up the hill.
• Pressure-test and disinfect new mains before putting them into supply, and keep livestock out of abandoned trenches.
• Keep the ram's own wetted parts clean too. The snifter deliberately admits air into the delivery vessel, so a fouled air chamber or a dirty snifter screen is an (admittedly minor) route for airborne material — worth wiping down when you service the machine.

What to test, and how often

• Continuously or weekly: free chlorine residual at the tank and at a tap, plus turbidity by eye. This is operational, not compliance testing — it is how you know the system is working.
• Periodically: microbial indicators — faecal coliforms or E. coli — as the meaningful test of whether the supply is safe. A presence/absence result is what matters; exact counts are a laboratory luxury.
• Once, at commissioning: a fuller chemical panel where the source is groundwater, and always check for obvious industrial or agricultural contamination in the catchment.
• After any event: flooding, a broken main, a dead animal in the source, or any change in taste, smell or colour.

Chlorination dosing calculator

Where the source is unprotected, chlorination is the last line of defence — the worked routine is in the treatment section above. This tool sizes the daily dose: enter the delivered flow, the target residual and the product's available-chlorine strength.

The arithmetic: mg/L × m³/day = grams of chlorine per day; product volume follows from its available-chlorine strength. Drip or gravity dosing must be checked against the residual at the far tap — a dose that is right in the tank is not necessarily right in the village, and the weekly comparator test is what actually proves the supply. Dosing details and the safe-handling routine are on Safety.

Details on the intake works live on Installation; tank construction and outlets are on Storage & distribution.