Why your condition says 110, not 125
The Building Regulations’ default water limit for new dwellings is 125 litres per person per day, but councils in water-stressed areas — much of the south and east of England — can require the optional standard of 110 l/p/d through a planning condition. If your decision notice mentions water efficiency, regulation 36(2)(b), or “110 litres”, this is what it means. Building Control will then expect your water calculation to demonstrate 110, not 125.
Is 110 hard to hit?
Harder than 125 — the 15-litre haircut removes most of the slack — but very achievable with deliberate fitting choices rather than exotic kit:
- Showers ~8 l/min rather than 10–12 (modern fittings at this rate feel fine, especially with aerating heads)
- Basin taps 4–5 l/min, kitchen tap ~6
- Dual-flush WCs at 4/2.6 litres
- A standard-size bath rather than a statement tub
- Efficient white goods if you’re specifying them
Where a client insists on the big shower or the big bath, the offsets have to come from everywhere else — or from rainwater/greywater harvesting, which the methodology credits and which sometimes turns an impossible spec into a pass.
Check before you order sanitaryware
The expensive mistake is buying fittings first and calculating second. Run your intended spec through our free WaterMonkey calculator — set the target to 110, watch the live PASS/FAIL, and adjust before anything’s ordered. The Building Control-ready report is £25 when you need it. Tricky condition wording or a marginal spec? Send it to us and we’ll sort it.