Septic Tank Installation in Lincolnshire — What You Need to Know (2026)

Whether you're building a new property in rural Lincolnshire, replacing an old cesspit, or upgrading a failing septic system, installing a septic tank is a significant investment. This guide walks through everything Lincolnshire homeowners need to know about septic tank installation — from choosing the right system to understanding costs and regulations.

Types of Septic Systems Available in Lincolnshire

Septic Tank with Soakaway

The traditional and most cost-effective option. Wastewater settles in the tank, partially treated liquid flows into a drainage field (soakaway) where it percolates through the soil. Requires suitable soil — Lincolnshire's varied geology means a percolation test is essential before choosing this option.

Cost (installed): £4,000-£8,000

Sewage Treatment Plant

A more advanced system that actively treats wastewater with bacteria and oxygen, producing effluent clean enough to discharge into a watercourse. The best option if your Lincolnshire property has clay soil, a high water table, or if you need to comply with the General Binding Rules for discharge to surface water.

Cost (installed): £6,000-£12,000

Cesspit / Cesspool

A sealed holding tank with no drainage field. The simplest to install but the most expensive to run — needs emptying every 4-6 weeks. Only recommended if soil conditions or space prevent a drainage field.

Cost (installed): £3,000-£6,000 (plus £1,500-£3,000/year in emptying costs)

Choosing the Right System for Your Lincolnshire Property

Soil Type Matters

Lincolnshire's geology varies significantly across the county:

• The Lincolnshire Wolds: Chalk and limestone — generally good drainage, suitable for septic tank soakaways
• The Fens: Heavy clay and peat, high water table — often unsuitable for soakaways; treatment plant or cesspit may be required
• The Lincolnshire coast: Sandy soils but high water table in some areas — percolation test essential
• Central Lincolnshire (around Lincoln): Mixed soils — test before deciding

A percolation test is mandatory before installing a septic tank with a soakaway. This determines whether your soil can accept the volume of water the system will produce. We can carry out this test as part of the installation planning process.

General Binding Rules (2020)

If your Lincolnshire property's septic tank discharges to a surface water (stream, ditch, river, etc.), it must be upgraded to a treatment plant or redirected to a drainage field. The rules don't apply if your system discharges to the ground via a soakaway.

The Installation Process

1. Site survey and percolation test — determine the right system and location
2. Building regulations approval — septic tank installations require Building Control notification
3. Environment Agency registration — you may need an exemption or permit depending on the discharge
4. Excavation — digging the tank hole and drainage field trenches
5. Tank installation — placing and connecting the tank to the property's drainage
6. Drainage field installation — laying perforated pipes in gravel trenches
7. Backfilling and reinstatement — covering the tank and restoring the ground surface
8. Commissioning and testing — checking the system works correctly

The entire process typically takes 3-5 days for a septic tank with soakaway, or 5-7 days for a treatment plant.

How Much Does Installation Cost in Lincolnshire?

Beyond the system itself, installation costs include:

• Excavation and groundwork
• Tank and pipework
• Drainage field materials (gravel, perforated pipe, membrane)
• Building regulations fees (typically £200-£400)
• Connection to existing drainage
• Commissioning and testing

For a standard installation with straightforward access, expect:

• Septic tank with soakaway: £4,000-£8,000
• Treatment plant: £6,000-£12,000
• Cesspit: £3,000-£6,000

Complex installations — poor access, high water table in the Fens, or replacement of an existing system — may cost more.

Maintenance After Installation

• Septic tank: empty every 12-18 months (£150-£250/year)
• Treatment plant: service annually, empty annually (£200-£400/year)
• Cesspit: empty every 4-6 weeks (£1,500-£3,000/year)
• Avoid planting trees near the drainage field
• Don't drive over or build on the tank or drainage field
• Use biological cleaning products to maintain bacterial activity

We install septic tanks, treatment plants, and cesspits across Lincolnshire including Lincoln, Sleaford, Boston, Louth, Gainsborough, Grantham, Stamford, and the surrounding rural areas.