Water supply for a one-off house: mains, group scheme or well

Ask Uisce Éireann whether it can connect your site before you finalise the design. The answer decides whether your house takes its water from the public network, a local group scheme or its own well, and each choice puts different costs and timing into your build. This guide compares the three and says what a lender will want to see.

Step 1: Ask about a mains connection

Uisce Éireann runs a pre-connection enquiry that checks whether a connection is feasible, then a connection application when you are ready. It advises making contact as early as possible in your project. Apply once you have planning permission, and ask for water and wastewater together if a sewer is also nearby.

The published standard charges for a single domestic home, assuming a gravity connection of up to 10 metres, are:

Item	Standard charge
Water, 25 mm pipe	€2,272
Wastewater, 100 mm pipe	€3,929

For runs beyond 10 metres, each extra metre up to 15 metres costs €358 for water and €442 for wastewater. Beyond 15 metres you pay the standard charge, the per-metre charges for the 10 to 15 metre section, and a quoted charge for every metre after that. The charging plan applies from 17 November 2023, so check the current page before you budget. Network extensions or upgrades can add cost, so ask in writing what your application assumes. The site works guide shows where the connection fits in the programme.

Step 2: If there is no mains, ask about a group water scheme

Some rural areas are served by a group water scheme: a local, community-run supply. Ask the scheme’s committee or manager:

• whether it will accept a new connection and what the connection fee and annual charge are;
• who lays and pays for the pipe from the main to your boundary, and who owns it;
• the most recent water test results and whether the scheme has any treatment or boil-water history;
• whether the scheme has enough capacity for one more house at peak times.

Get the answers in writing and keep them. A lender or valuer may want a letter from the scheme to confirm that your house has a permanent supply.

Step 3: Otherwise, a private well

On many rural sites the answer is a private well: a drilled or dug source on your own land. The owner is responsible for water quality, which means you arrange the testing and any treatment.

Plan for these costs and checks:

1. A well driller, who sinks the borehole and lines it. The price depends on depth and rock, so get a quote based on what is known about your area.
2. A yield test to prove the well delivers enough water for a household in dry weather.
3. A laboratory water-quality test for bacteria and chemical parameters. Ask the laboratory what it recommends for a domestic supply, and get a quote rather than assuming a price.
4. Treatment where the test shows a problem, for example filtration or ultraviolet disinfection. The results decide the equipment and the running cost.
5. A pump, a pressure tank and pipework to the house.

The site suitability assessment and the wastewater guide matter here, because there are required separation distances between a well and a wastewater system, and the layout of the site may only allow one arrangement. Fix the positions of the house, the percolation area and the well on one drawing before you order anything.

The well grant is not for new builds

The well grant requires the home to be at least seven years old, normally occupied by the applicant and unable to connect to public or group water. A house you are building does not qualify. Put the full well cost in your budget. For an older house, the council gives approval before the work starts.

What lenders and valuers ask for

Your lender needs a house that is habitable and can be valued. In practice that means evidence of a permanent water supply. Ask before drawdown:

• Mains: a copy of the connection offer and, at completion, proof the connection is made.
• Group scheme: a letter from the scheme confirming the connection and charges.
• Well: the driller’s certificate, the yield result and a recent laboratory report showing the water is safe to drink.

Also ask your solicitor whether you need a legal right of way or an easement for a pipe crossing someone else’s land. The mortgage guide and the drawdown guide show where these checks fall in the lender’s process.

Insurance

Tell your insurer which supply you are using. Drilling and trenching on site are contract works, and damage to a neighbour’s pipe or a public main while digging is a liability risk. Check that your policy covers it before the digger arrives. The insurance guide lists the policies a self-build normally needs.

Which route is cheapest and quickest?

No one answer fits every site. A short mains connection has a fixed, published price and low ongoing risk. A group scheme can be cheap per household but depends on the committee’s terms. A well has no connection fee, but costs for drilling, testing and treatment are uncertain until the first test result. Compare the whole cost, including the pump and treatment, and the time each option needs, against your programme.

Timing and the programme

The water supply has to be ready before the plumber arrives at first fix, and often earlier: the builder needs water on site for mixing, cleaning and the screed. A mains connection depends on Uisce Éireann’s programme, which is outside your control, so apply early and ask for the expected date in writing. A well can be drilled while you wait for other consents, but only once the positions are agreed and the driller has access across the site. Test the well water before you commit to the pump and treatment equipment, because the result decides what you buy. If the supply will not be ready when the builder expects it, tell the builder and your lender’s engineer, since a delay to the first fix pushes back the next drawdown.

Temporary water on site

Ask the builder what supply they will use during the build. Some use a temporary standpipe on the mains, which Uisce Éireann must approve, others bring water in a tank. A well that is not yet tested should not be used for drinking on site. Agree who pays for the temporary supply in the building contract. See the builder and contracts guide for what to put in writing.

Questions to ask

1. Uisce Éireann: is a connection feasible, how far is the main from my boundary, and what is the total charge?
2. Group scheme: will you accept a new connection, and what is the charge and the latest test result?
3. Driller: what depth do you expect, what is the price, and what happens if the first hole is dry?
4. Designer: where do the house, the well and the wastewater system go, and is the separation distance met?
5. Lender: what evidence of water supply do you need before each drawdown?

Once you know your supply, make sure the cover for the works is in place before the digger starts. See what cover you need.