Setting up a house to catch rainwater

The figure to start from is "700 Gallons/3,150 litres", set as a home's recommended minimum. It comes from the Rainwater Harvesting Planning Guideline from the Ministry of Economic Growth and Job Creation, hosted by the Water Resources Authority and dated Oct 2023. The same document says about 15% of Jamaicans rely on rain as their main supply.

Accepted tank types are stone, concrete, galvanized iron and "thermoplastic polyethylene (black tanks)". A full 3,150 L is heavy, so its position matters: see roof or ground. To size for your own household, work through how big a tank.

Our arithmetic: 1 mm of rain on 1 square metre of roof is 1 litre. Measure the roof's footprint, not its sloped surface, and multiply.

To fill 3,150 L from that roof takes about 32 mm, plus the flush. Real catch is lower, since gutters overflow and splash in heavy rain. We haven't given parish rainfall figures because we didn't source any; use records for your own area when deciding how much tank you need.

Zinc is, if you mean to drink the water. The guideline lists these for potable use: "metal (including zinc and decra-tiles), wood shakes (shingle), concrete and clay". Asphalt types go on its non-potable side.

WHO's drinking-water guidance agrees on coatings, saying "roofs with bitumen-based coatings are generally not recommended", and warns against lead paint. If an old roof was painted and nobody knows with what, treat that as a question before you plumb it to a drinking tap. What it takes to make the water drinkable is a separate job from catching it.

A leaf screen, then a way to throw away the first dirty water.

• Screens: openings no larger than 1.27 cm (0.5 in), per the guideline.
• First flush: the first 10 gallons (45.5 L) of runoff "during any rain event must be diverted" from the tank.
• Downpipes: WHO asks for mesh over them and clean gutters.

Dust and droppings wash off the roof at the start of each shower, which is why that first water goes to waste. For gutter work at roof level, pay someone, and pick a dry, calm day. Never go up in wet weather, in wind or under a storm warning.

No. For a property on National Water Commission (NWC) or other utility water, the guideline says it "must install a separate or dual plumbing system for indoor use". Its pump, the document adds, "should not be connected" to the public main, and a reflux (non-return) valve is required.

The point is to keep tank water from getting back into a supply other people drink. Non-potable indoor lines get a 5-micron filter and purple or another specific colour of pipe, so nobody mistakes them later. Our pump and pressure tank stack explains the pump side. Never remove or bypass that valve.

Not that we could confirm. The Gleaner reported in April 2023 that Minister Samuda said no to a law, with guidelines to be gazetted instead. Its August 2026 editorial doubted that ever happened, saying "no such guidelines were ever promulgated".

A power may be coming. Clause 61 of the 2017 Building Bill lets the Minister make regulations "for water harvesting, including requiring provision to be made for the storage of rainwater runoff", but that is Bill text, not necessarily the Act as passed. The Kingston and St Andrew corporation's checklist showed no tank figure either. Ask your local approving body when you apply.

The guideline wants a check "by a certified plumber or other relevant professional" before pipes and tank are covered, then once a year. There's a catch: we could not confirm any Jamaican plumber licence or register, so ask what "certified" means for the person in front of you. We suggest questions to put to a plumber.

Between inspections the jobs are plain ones: gutters clear, screens whole, the tank lid tight. Keep mosquitoes out of the tank, and read the tank cleaning stack before anyone reaches for a brush. Nobody climbs inside.

The National Housing Trust's SMART Energy Loan does, on its own undated page read 2 Nov 2026. It lends "up to $2.5 million" (J$), and its list of uses takes in rainwater systems with their "tanks and pumps". You must pay into the Trust, and own and live in the house.

The only word on interest is "concessional", so get the real rate and term in writing before signing. We haven't priced a system, since the documents we read give no Jamaican cost figures. Get written quotes in J$ that split tank, pump, gutters and plumbing, so you can compare them line by line.