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Glossary

Abbreviations and terms, in plain language.

OPEX, ROI, M&V, building surveys, ISO 50001, CSRD/ESRS, public procurement — terms from water and energy saving, audits and ESG, explained in the customer's language. We link to this glossary from across the site.

Economics & decisions

OPEX — operating expenditure

The running costs of a building — water, energy, servicing. Saving at the outlet and on flushing cuts OPEX immediately, without a large investment. The opposite of CAPEX.

CAPEX — capital expenditure

A one-off investment in assets or refurbishment. Retrofitting saving components is low CAPEX compared with refurbishment, with a fast payback.

ROI — return on investment

How long it takes for the money spent to come back out of the costs saved. For saving components at the outlet the payback is usually a matter of months — see our reference.

TCO — total cost of ownership

Purchase, operation and maintenance added up over the whole service life — not just the purchase price. A cheap component with high consumption has a higher TCO than a dearer, efficient one.

Audit & measurement

Water and energy audit

An assessment of consumption and of the state of the equipment in a building, plus a proposal of measures. We offer three levels — basic (free), survey and measured. See Services & audit.

Plumbing survey — inventory and condition of the installations

A complete inventory of the plumbing installations: what equipment is in the building, what condition it is in (scale 1–6) and when it has to be replaced. Vendor-neutral — it also serves as evidence for warranty claims. It is a survey of the plumbing, not of the building as a whole.

reAUDIT — our audit application

The software the audit runs in: we collect data on site, compute the condition of the equipment and generate the outputs. The basic assessment, the survey and the measurement are simply different amounts of data you order within reAUDIT — not three different products.

Baseline — the starting (measured) consumption

The actual consumption measured before the work, against which the saving achieved is compared. The basis for M&V.

M&V — measurement & verification

The methodology for measuring and evidencing the actual saving by comparing the state before and after. The measured audit produces figures that hold up in a report and with the client.

Expected versus measured saving

The expected saving is an estimate from a calculation (calculator, quotation, basic audit). The measured saving is evidenced by measurement (case studies, measured audit, M&V). We never mix the two — we do not present an estimate as evidenced.

Retrofit — fitting into an existing installation

A saving solution fitted into an existing installation without refurbishment — a regulator at the outlet, say, or a dual flush in the existing cistern. The wearing part is the insert, not the tap; replacing it keeps the tap in service, which is waste prevention.

Plumbing and drainage installations — plumbing and drainage installations

The water and drainage pipework in a building and the equipment connected to it (taps, WCs, urinals). The subject of the survey.

Vendor-neutral — brand-independent

Assessing the condition and proposing a solution regardless of manufacturer. It maps the real state objectively and also serves as evidence for warranty claims on other makes.

ESG & certification

ESG — environmental, social, governance

The framework for non-financial corporate reporting — impact on the environment, on society and the way a company is run. Water and energy savings bring quantified figures into the E section. See ESG & compliance.

CSRD — the EU sustainability reporting directive

Corporate Sustainability Reporting Directive — the European directive widening companies' duty to report sustainability under the ESRS.

ESRS — European reporting standards (E1, E3)

European Sustainability Reporting Standards — the specific standards under CSRD. E1 = climate and energy, E3 = water and marine resources, E5 = resources and the circular economy. Our savings supply figures for E1 and E3; E5 is where waste prevention belongs, described as a measure rather than as a figure.

Waste prevention — the highest tier of the waste hierarchy

Measures taken before a thing becomes waste. Article 3(12) of Directive 2008/98/EC names among them extending the life of products. It is a tier above recycling — what gets recycled is what has already become waste. Retrofit into a working tap belongs here; it is not “preparing for re-use”, which concerns things that have already become waste. ⚠ How much waste is thereby avoided we do not quantify — there is no accepted methodology.

ISO 50001 — the energy management standard

The international standard for an energy management system (EnMS). The measured audit supplies both the input data and the proof of improvement.

EnMS — energy management system

Energy Management System under ISO 50001 — a way of systematically tracking and reducing energy use.

BREEAM / LEED — building sustainability certification

International rating systems for building sustainability. An evidenced water and energy saving earns credits in the relevant categories.

Ecolabel — the EU ecolabel

The EU environmental label; criteria for services and buildings may include water efficiency. Material for green procurement.

For sanitary fittings it can only be granted to a complete fitting, not to a component fitted into it (Decision 2013/250/EU) — nor can it be inherited from the fitting the component goes into. That is why we do not promise the ecolabel for regulators and aerators. Procurement rules allow for this: under Article 44(2) of Directive 2014/24/EU the authority must accept other appropriate evidence — for a component that means a test report under EN 246.

GPP — green public procurement

Building environmental criteria into public-sector purchasing. Water and energy saving is a common award criterion.

Public procurement

Public procurement law — the rules for public purchasing

The national law governing purchases by the public sector. It sets out how a supplier proves its qualification and what form references take. Every EU member state has its own, built on Directive 2014/24/EU.

References in tenders — proving technical capability

Under Article 58(4) and Annex XII of Directive 2014/24/EU a supplier proves its experience by a list of earlier contracts. ⚠ The form differs by the type of contract: for works the list is accompanied by certificates of satisfactory execution, whereas for supplies and services a list stating the value, the date and the recipient is enough — a certificate is not required there.

What we deliver are supplies and services. A signed confirmation from the client is therefore more than the rules ask for — and that is why we put it in our case studies. Each member state transposes this into its own procurement act, so the exact section number differs by country.

Preliminary market consultation

Before launching a tender the contracting authority consults the market so as to set the specification correctly — expressly allowed by Article 40 of Directive 2014/24/EU and transposed in every member state. We help with the background material, so that the specification matches the saving solutions that actually exist.

ESPD — European Single Procurement Document

European Single Procurement Document — the supplier's self-declaration that it meets the qualification requirements, used in the opening stage of a tender.

Water technology

Flow regulator / aerator

A component at the tap outlet that lowers the flow while keeping showering or washing comfortable. The basis of saving at the outlet.

Aerator

It draws air into the stream — the stream still looks and feels full while using less water.

EN 246 — the standard for flow straighteners

General requirements for flow straighteners, that is for aerators and regulators. Among other things it lays down that the nominal flow is stated at a pressure of 0.3 MPa (3 bar) — without the pressure, a flow figure cannot be compared with anything.

Products are classified by nominal flow into classes Z, A, S, B, C and D. The standard expressly allows for flows outside those classes — so a low-flow component is not a departure from the standard. On products with an integrated regulator the nominal flow in l/min is given directly instead of a letter class, which is why you will not find a letter on them.

Laminar stream

A straightened, continuous stream that does not break into aerosol. Hygienically preferable — see water hygiene and safety.

Dual-flush — two-volume flushing

Two buttons and two flush volumes (small and large). It can be retrofitted into an existing cistern — see efficient flushing.

WC stop

Interrupting the flush — you use only as much water as you need.

Waterless urinal

A urinal with no flushing water; a trap or a cartridge holds the odour back. See waterless urinals.

Legionella

A bacterium that multiplies in tepid, standing water in the pipework. Controlling temperature and flow lowers the risk — related to water safety.

Missing a term? Write to us at save@rewater.eu and we will add it.
From terms to figures

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