Confluence Water Partners
CONFLUENCEWATER PARTNERS
Interactive Planning Tool

Water Security Planner

Configure your estate's water-resilience profile and compare the cost of staying on municipal supply, a zero-upfront utility model, or owning the asset — over the long term.

Figures are indicative estimates for planning and discussion only — not a quotation or financial advice. Adjust the assumptions to match your estate, or ask us to model it precisely.
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Your estate

The essentials — most boards know these from a recent municipal bill.

Your priorities

What matters most, and how resilient you want to be.
How much of the estate’s water you aim to supply from an alternative source (reuse, borehole or a utility plant). The balance stays on municipal supply. Higher means greater resilience — but a larger plant and more capital.
Advanced assumptions (calibrate before client use)
Upfront build cost per kilolitre of daily output capacity. At R38 000, a 50 kL/day plant costs about R1.9m. Smaller plants cost more per unit.
Cost of backup storage tanks per kilolitre held. Applied to the stored-supply volume set by “Days of stored backup supply”.
Once-off cost of generators, inverters or solar to keep the plant running through load-shedding. Only added when “Include backup power” is switched on.
Yearly upkeep — servicing, spares and membrane replacement — as a percentage of the plant’s build cost. Added to running costs each year.
How far the supplier-dependent figures (utility rate, plant CapEx, operating cost) might swing. This sets the width of the low–high ranges and the shaded bands on the chart. The municipal baseline isn’t flexed — it comes from your own bill.
Municipal sewer/sanitation charge per kilolitre of billed discharge — a cost estates pay on top of water, often 60–90% of the water rate.
The share of water use the municipality treats as discharged to sewer and bills for. On-site reuse recycles the secured volume, so it no longer counts as discharge.
Note: a higher % means a bigger saving \u2014 the more you're billed to discharge, the more on-site reuse avoids. It only affects the reuse option.
Recommended pathway

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Secured on site is the share of the estate's water you'd supply independently — from on-site reuse, a borehole or a utility plant — instead of buying it from the municipality. The remainder stays on municipal supply.

Cumulative cost over 10 years

Stay on municipal Water-as-a-Service Own the asset Shaded = estimate range

Benchmark Reference · South Africa

Starting figures for calibration

Indicative market rates to seed the assumptions above — reviewed June 2026. Tap Use to load a municipality's water rate. Always confirm against the estate's current bill and firm supplier quotes.
Municipality (2025/26)Domestic R/kL (higher use)Business / bulk R/kLAnnual increase
JohannesburgR60 – R83 (30 kL+)R68 – R72~13.9%
Cape TownR37.72 (≤24.5 kL) · R62.04 (≤35 kL)R43.54 (incl VAT)6.8%
eThekwini (Durban)~R32 – R45 (indicative)Bulk ~R10 (Umngeni)~12 – 15%

On-site plant economics

  • Plant CapEx (package / reuse): R25k – R60k per kL/day
    Small plants cost more per unit; SA municipal-scale activated-sludge ≈ R10k/kL·day at 10 MLD.
  • Operating cost: R8 – R20 / kL (energy, chemicals, membranes, sludge, staff)
  • Storage tankage: R2 000 – R5 000 / kL
  • Desalination (upper reference): R15 – R45 / kL fully loaded

Context for escalation

  • Metro water tariffs rose 7 – 15% in 2025/26 (Cape Town 6.8%, Joburg ~13.9%, eThekwini ~12–15%).
  • Bulk water boards (Rand Water, Umngeni–uThukela) supply metros at roughly R8 – R11 / kL, rising ~13–15%/yr.
  • A 7–11% escalation default is conservative — water has outpaced CPI for years.
  • Sanitation / sewer is billed on top of water (often 60–90% of water use). It's now in the baseline, and on-site reuse trims it.
Sources: municipal tariff schedules (City of Johannesburg 2025/26; City of Cape Town 2025/26) and reporting (IOL, News24, The Mercury); treatment-cost benchmarks from industry sources (The Water Network SA project data, package-plant and desalination references). Figures vary by metering (bulk vs per-unit) and VAT treatment. Reviewed June 2026 — verify before client use.