Does stump grinding damage pipes and cables?

It can, and that is the honest answer. A stump grinder cuts to roughly 15 to 30 centimetres below ground level, the same band of soil that garden water pipes, electric feeds to a shed, telecoms ducts and garden lighting run through. What stops damage is not the machine but the ten minutes before it starts: asking what is buried where, reading the ground for clues, running a cable avoidance tool over the area and digging by hand where anything is suspected. A contractor who does that rarely hits anything. One who wheels the grinder straight off the trailer is gambling with your garden.

How deep a grinder actually goes

A stump grinder is a spinning wheel with carbide teeth that sweeps side to side, taking the stump down in layers and turning it into chippings. Typical practice is to grind 15 to 30 centimetres below grade, enough to lay turf, gravel or a patio base over the top. Machines can go deeper, and some operators will if you are replanting in the same spot, but that costs time and carries more risk.

What grinding does not do is remove the root system. Lateral roots stay in the ground and rot over several years. If you need those out too, that is stump removal, which means excavation and a bigger hole.

What is buried near a stump

Trees get planted near boundaries, sheds, drives and house walls, which is exactly where services run. Expect any of these within a metre or two:

• The water supply pipe. From the boundary stop tap into the house, the supply pipe is the homeowner's responsibility, not the water company's, even where it crosses someone else's land: Severn Trent's responsibility ends at the highway boundary. It is usually the service that gets hit, and usually yours to pay for.
• The gas service pipe running from the meter box or the main into the property.
• Electric supply cables, and any armoured cable feeding a shed, garage, garden office, pond pump or outside socket. Garden runs are often shallower than mains, and laid by someone who recorded nothing.
• Telecoms and broadband, either a buried drop from a pole or a duct from the footway.
• Drains and sewers, including old clay foul runs, rainwater gullies and soakaways.
• Irrigation and garden lighting. Low-voltage cable and blue MDPE pipe are often a spade's depth down.

Old plans rarely show any of this, which is why our quote form asks whether there are known pipes, cables or drains within two metres of the stump. "Not sure" is a good answer: it flags the job for a closer look.

How a careful contractor checks

The HSE's guidance on working near buried services, HSG47, sets out three stages that apply as well to a back garden as to a road: plan the work, locate and identify what is there, then excavate safely. In practice:

1. Ask you. You know where the shed cable went in and which bed the plumber dug up. The most useful check, and free.
2. Read the ground. A stop tap cover, a meter box, a manhole, a gulley, a line of settled ground or a joint box in the pavement all say something about what runs where.
3. Check any plans. Deed plans, drainage drawings and extension paperwork can show service routes. LinesearchbeforeUdig is a free search querying more than 160 asset owners across a large share of Britain's buried networks, though it will not show the cable you ran to your own shed.
4. Scan with a CAT and genny. A cable avoidance tool detects signals from buried cables and metal pipes, and a signal generator traces a specific service. It will not find plastic water pipe with no tracer wire, so it is one check among several.
5. Hand-dig where there is doubt. HSG47's approach is to expose a suspected service by hand rather than let a machine find it. A trial hole takes minutes.
6. Set a safe limit. If a service is confirmed inside the grinding area, grind only to a safe distance and finish by hand, or change the plan.

Ask each firm how they check. A good answer is specific. A shrug is a warning.

If a service does get hit

• Electricity. Stop, keep everyone back, do not touch the machine or the cable, and call the network operator's emergency number. A live cable strike can cause severe burns from the arc, not just shock.
• Gas. Stop, no ignition sources, get everyone clear, call the national gas emergency line on 0800 111 999.
• Water. Turn off at the stop tap and call the supplier. If it is your supply pipe, it is your repair.
• Drains or telecoms. Less dangerous, still disruptive, and not cheap.

Who pays

It depends on why it happened. If the contractor was told where a service was, or should reasonably have found it, and ground through it anyway, that is a claim on their public liability insurance. If you said there was nothing there and there was, your position is much weaker. If the service was genuinely unmapped, an insurer may still argue.

Before work starts, ask for the public liability certificate and check that the business name matches the one quoting you, the policy is in date, and it covers tree and stump work rather than general gardening. Get the plan in writing, including grinding depth. Our guide to tree surgeon qualifications and insurance covers what to ask for.

When grinding is not the answer

Sometimes the right call is not to grind at all. A confirmed service inside the grinding zone usually means hand excavation, or leaving part of the stump, rather than risking a repair bill. A stump hard up against a wall, drive or foundation may not give the machine clearance, and vibration next to shallow footings is not worth it. A narrow side gate may mean a smaller grinder or a different method. And if the area is becoming a shrub bed, a stump left to rot is cheap and harmless: it is lawn, paving and replanting that make grinding worth paying for.

What it costs

On our price card, standalone stump grinding is £120 to £180 for a stump under 30cm across, £180 to £280 at 30 to 60cm, and £280 to £400 over 60cm, with a £150 job minimum and waste included. Several stumps in one visit are cheaper per stump, so ask for a price for the lot. See stump grinding and the stump grinding cost guide. If the tree is still standing, start at tree removal.

We are an introducer: we pass your enquiry to one vetted local specialist covering your area, who confirms a fixed price from your photos. See what to photograph for a tree quote.