Restaurant Water Filter System — Ice, Coffee, Dishwashing & Drinking Water

A restaurant combines four water uses with different quality needs: ice making, coffee and tea brewing, dishwashing and steam cooking. One incoming line rarely serves all four well. Chlorine and dissolved solids that are acceptable at a hand-wash sink become visible in a glass of ice, and hardness that passes through a dishwasher leaves film on glassware and scale on heating elements.

Ice is the most sensitive point. Freezing pushes dissolved salts toward the centre of the cube, so high TDS or hardness produces cloudy, brittle ice that melts quickly and dilutes drinks unevenly. Chlorine and chloramine carry odour into ice and cold brew. Coffee extracts aroma compounds, and chlorine binds them; high alkalinity neutralises the acids that give brightness, so the same beans taste flat.

Dishwashers and combi steamers are equipment problems rather than taste problems. At 200 ppm hardness, scale forms on heating elements and spray arms within months, raising energy use and service calls. Well water adds iron, manganese and turbidity, which stain fixtures and clog aerators. Water quality also changes with the season: municipal supplies switch sources, and well levels draw down in dry months. A filter sized on one test may be marginal six months later, so design for the worst case and keep pretreatment easy to upgrade.

Sizing starts from two numbers: daily demand and peak hourly flow. For food service, a planning value of 15–30 L per seat per day is typically used for ice, beverages, kitchen preparation and washing. It is not the total building water demand, which also includes toilets and cleaning. Daily demand in cubic metres equals seats multiplied by litres per seat, divided by 1,000. If the restaurant is already trading, replace the estimate with 7–14 days of metered consumption; the meter usually shows a sharper morning prep peak than the seat count suggests.

Peak flow equals daily demand multiplied by a peaking factor of 1.5–2.0, divided by 8–10 operating hours, plus 10–15% margin. A 120-seat restaurant at 20 L per seat uses 2.4 m³/day; its peak is about 0.47 m³/h. A 0.5 m³/h RO unit with 1–2 m³ of storage covers the lunch and dinner rush without oversizing the membrane.

Use the table below to move from daily demand to a complete train. Storage is normally sized for one to two hours of peak demand; if the ice machine and the coffee bar run at the same time, check the combined draw with a simultaneity factor of 0.8–0.9. Keep 10–15% spare capacity for membrane fouling and seasonal trade. For a new build, add the ice machine, coffee bar and drinking fountains as separate loads rather than one lump figure; the sum is usually more accurate than a per-seat estimate.

Maintenance follows consumable intervals rather than taste complaints. Replace the 5 µm cartridge every one to three months, the carbon block every three to six months, and check softener salt weekly. Resin typically lasts three to five years, RO membranes two to three years, and UV lamps 9,000–12,000 hours. Record permeate flow, conductivity and pressure daily; a 10–15% drop in normalised flow means it is time to clean or investigate. Keep a log book at the skid; it is the fastest way to separate a fouled membrane from a failing pump.

Ice machines and coffee equipment also need their own sanitation schedule, because the filter protects the water but not the machine downstream. Clean ice bins and dispense spouts as the manufacturer specifies, backflush coffee machines daily, and sanitise the storage tank and loop quarterly. Keep a spare set of cartridges and a spare UV lamp on site so a failure does not stop service.